UNDERFLOOR HEATING a Solution Or a Problem?

UNDERFLOOR HEATING A solution or a problem?

Joakim Larsson

Master Thesis in Energy-efficient and Environmental Buildings Faculty of Engineering | Lund University Lund University Lund University, with eight faculties and a number of research centers and specialized institutes, is the largest establishment for research and higher education in Scandinavia. The main part of the University is situated in the small city of Lund which has about 112 000 inhabitants. A number of departments for research and education are, however, located in Malmö and Helsingborg. Lund University was founded in 1666 and has today a total staff of 6 000 employees and 47 000 students attending 280 degree programs and 2 300 subject courses offered by 63 departments.

Master Program in Energy-efficient and Environmental Building Design This international program provides knowledge, skills and competencies within the area of energy-efficient and environmental building design in cold climates. The goal is to train highly skilled professionals, who will significantly contribute to and influence the design, building or renovation of energy-efficient buildings, taking into consideration the architecture and environment, the inhabitants’ behavior and needs, their health and comfort as well as the overall economy.

The degree project is the final part of the master program leading to a Master of Science (120 credits) in Energy-efficient and Environmental Buildings.

Examiner: Hans Bagge (Building Physics) Supervisor: Dennis Johansson (HVAC) Keywords: Underfloor heating, Energy, Thermal mass, Energy efficiency, Heating systems

Thesis: EEBD–15/10

Underfloor heating- a solution or a problem Table of content 1 Background ...... 1 1.1 Energy and environmental issues 1 1.1.1 EU directives 1 1.1.1.1 National targets 1 1.1.2 Energy in Swedish residential buildings 1 1.2 Underfloor heating 2 1.2.1 Possible benefits of underfloor heating 2 1.2.2 Possible disadvantages with underfloor heating 2 1.2.3 Floor materials 3 1.2.4 System control 4 1.2.5 Underfloor heating in combination with heat pumps 4 1.3 Objectives 4 1.4 Limitations 4 2 Method ...... 7 2.1 Questionnaire study 7 2.2 Indoor climate measurements 8 2.2.1 Loggers and outdoor climate 8 2.2.2 Sorting of values 8 2.2.3 Analyses of the measured houses 9 2.3 Simulations 9 2.4 Industry knowledge and directives 9 3 Results and analysis ...... 11 3.1 Questionnaire study 11 3.1.1 Overall satisfaction 11 3.1.2 Discomforts 12 3.1.2.1 During heating season 13 3.1.2.2 During the whole year 13 3.1.3 Flooring materials 15 3.1.3.1 Cold floors 17 3.1.3.2 Varying temperature with different flooring materials 17 3.1.4 Wanted temperature 19

Underfloor heating- a solution or a problem 3.2 Indoor climate measurements 19 3.2.1 Temperature measurements 20 3.2.1.1 Distribution of logged temperatures 20 3.2.1.2 Influence of the outside temperature 25 3.2.1.3 Comparison between the two measured systems 26 3.2.2 Humidity measurements 27 3.2.2.1 Comparison between the two measured systems 33 3.2.2.2 Influence of the outside relative humidity 34 3.2.3 Analysing the measured residences 35 3.2.3.1 Comparing with the questionnaire answers 35 3.2.3.2 Moisture addition 36 3.3 Simulations 38 3.3.1 Energy simulations 39 3.3.2 Thermal mass 40 4 Discussion ...... 43 4.1 Industry knowledge 43 4.2 Questionnaire study 43 4.3 Indoor climate measurements 45 4.4 Simulations 46 5 Conclusions ...... 49 6 Future work ...... 51 References ...... 54 Appendix A ...... 56 Appendix B ...... 57

1 Background

1.1 Energy and environmental issues

According to the Intergovernmental Panel on Climate Change, IPCC, it is clear that humans have had a grave impact on the climate changes that has taken place since the 1950s. The atmosphere and the oceans are getting warmer which causes ice and snow to melt, raises the sea-levels and increases the risk for natural disasters. The anthropogenic emissions of greenhouse gases are at an all-time high, much because of the persistent use of fossil fuels. 80% of the world’s energy use still comes from fossil fuels. This might come as a surprise since the negative impact of using fossil fuel is well known and that the environmental question often is high on the political agenda. (IPCC,2013) There are several reasons for this, one being the exponential increase of human population, another is that although highly developed countries use of fossil fuel decreases the use in less developed countries increases as they are reaching for quick and cheap changes. Renewable energy sources, which have a much lower emission of greenhouse gases than fossil fuels, are becoming more evolved and more common. This is a step in the right direction, but it is not the only solution. In order to more effectively decrease the environmental impact the use of energy should be lowered. 1.1.1 EU directives In March 2007 the European Union leaders set new targets for its members in order to try reducing the environmental impact and to support the development of renewable energy sources. The three major objectives are; a 20% reduction in EU greenhouse gas emissions from 1990 levels, raising the share of EU energy consumption produced from renewable resources to 20 % and a 20% improvement in the EU’s energy efficiency. Because of these three key objectives the targets are known as the “20-20-20” targets and are aimed to be fulfilled in 2020.

1.1.1.1 National targets The Effort Sharing Decision sets national targets for 2020 which is binding for each member in the European Union. This decision targets the 60% of greenhouse gas emissions that is not produced by the industrial sector and therefore not covered by the EU Emission Trading System. The targets which is expressed in percentage-change from 2005s levels is decided by the wealth of each country, this means that a wealthy country have to lower its emissions more than a less wealthy. A less wealthy country is even allowed to increase their percentage in order to leave space for a growing economy, the main goal is that in 2020 the greenhouse gas emissions (covered by the Effort Sharing Decision) from all members of the European Union should be lowered by 10%. 1.1.2 Energy in Swedish residential buildings As set by the Effort Sharing Decision Sweden needs to lower its greenhouse emissions outside the industrial sector with 17% compared to 2005s levels. Greenhouse gases from residential buildings fall under this category and will be addressed by improving the energy performance of buildings. (Council of European Union, 2015)

Underfloor heating- a solution or a problem In 2013 the energy consumed within residential buildings in Sweden was 63 427 GWh and approximately 87% (55181 GWh) of this energy was used to heat the buildings. A good way to reduce the consumption of energy and thereby lower the impact on the environment could be to use more efficient heating methods. (Statistikcentralen, 2014) 1.2 Underfloor heating

Underfloor heating is often promoted to be an energy efficient heating method and is becoming more and more common in Swedish single family houses. 61% of all single family houses built in Sweden during 1996-2005 was equipped with underfloor heating, which is a large increase compared to 1986-1995 where only 10% of new buildings where equipped. (Betsi, 2009) An underfloor heating system functions similar to the traditional radiator heating system, but instead of having hot water running through and heating small surfaces, such as radiators that are placed inside the room, the hot water runs through pipes that are casted in the foundation under the floor or placed underneath the flooring material and therefore heats up the larger floor area. According to the Swedish authorities the floor surface should not exceed 27°C. (T2, 2002) 1.2.1 Possible benefits of underfloor heating Underfloor heating should take away the factor of cold floors which is a desirable advantage for many. It is also hidden underneath the flooring and does not take away space or affect the appearance of the living area. The human head thrives in a temperature of about 18-20°C but the feet wants a temperature about 5°C higher than that. If a room is heated from the floor the general temperature in the room should thereby be able to be lower, because the human feet is the primary sensory organs for temperature i.e. if the feet are warm we feel warm. This should, according to experts, allow for a room temperature that is 2-3°C lower and an energy saving of about 15% than if a conventional radiator system were used. (Boverket, 2015) Since radiators are relatively small in area the water needs to be relatively hot in order to heat an entire room, the radiated heat will also mostly be located around the radiator. This should not be the case for underfloor heating. Since the entire floor is heated there is a lot of contact between the heated floor and the air, which should allow for lower water temperatures in the system and more dispersed heat in the entire room. (Boverket, 2015) Utilizing the thermal storage in a building is often a good way to lower the amount of energy needed to keep a building heated. Since the entire floor is heated when underfloor heating systems are used there is a lot of mass where the thermal energy can be stored. This stored energy should help to keep a uniform indoor temperature throughout the day and lower the energy need. 1.2.2 Possible disadvantages with underfloor heating Floor heating systems radiates the same amount of heat up to the building as it does down to the foundation, it is therefore important to have a lot of insulation in the foundation to prevent the energy from being wasted in to the ground. According to Swedish authorities and experts it is recommended to have at least 250 millimetres of insulation below the floor

Underfloor heating- a solution or a problem heating system. This will lead to a higher initial cost of the system and can be hard to implement when renovating or rebuilding. (Boverket, 2015) It is also debatable that since such a large surface is heated by the system it is not to recommend if the demand of energy is low. It will always take a certain amount of energy to heat this large surface, which leads to that the minimum amount of energy that can be provided by an underfloor heating system is higher than systems that uses smaller surfaces. If the system is used in a well-insulated building with an energy demand that is lower than the minimum energy that can be provided, the system may turn on and off and thereby provide uneven temperatures and waste energy. This can make the underfloor heating system difficult in new buildings where it is common to have a lot of insulation in order to reach the energy goals. Since it is common to have the floor heating casted inside the concrete, which can store a lot of heat, there will be a time delay before any changes of heat supply will influence the temperature of the room. This means that if the temperature outdoor rapidly changes it will take time before the heating system adapts, which can lead to both overheated and cold indoor climate. If the building has large windows and a slowly adapted heating system, solar energy in combination with the stored energy in the concrete can rapidly increase the indoor temperature and lead to uneven temperatures and overheating. It is common to place radiators underneath windows to avoid downdraughts from the cold window surfaces, which is not possible with an under floor heating system. To avoid this complication the Swedish authorities and experts recommend that window constructions with a U-value below 1.0 W/(m²K) are installed. These window constructions are expensive and this will raise the price of installing underfloor heating both in new buildings and renovations. (Boverket, 2015) It can also be argued that there is an increased risk of water damage with a floor heating system compared with other heating systems. If there is a leak in any of the water pipes in the floor it would be hard to detect in time and the water damage it causes could be very extensive. A discussion with Vattenskadecentrum (Water damage center) revealed no known, apparent increase of such risks. 1.2.3 Floor materials The type of flooring material chosen when using an underfloor heating system can have a high impact on how the system works. If a heavy material, such as stone that stores a lot of heat, is chosen it should create a system that takes a relatively long time to influence the temperature in the room. When the outdoor temperature quickly drops this can help to keep an even indoor temperature, but when the outdoor temperature quickly raises or the sun starts to shine the combined energies could create overheating since the heating system is slow to adapt. If a lighter material, such as parquet floor, that does not store so much heat, is chosen the heating system should be quicker to adapt to changing conditions. If the outdoor temperature then quickly raises or the sun starts shining the flooring material does not have a lot of energy stored and will faster adapt. The same goes for if the temperature outside rapidly drops.

Underfloor heating- a solution or a problem 1.2.4 System control There are different ways on how the underfloor heating can be controlled. The standard being a thermostat either in the floor or in the room, this could create problems since heat from other sources is not taken under consideration. There is a more energy efficient way where the thermostat measures the temperature both in the floor and in the room at the same time and thereby utilizes heat from other sources such as the sun or people. (T2, 2002) 1.2.5 Underfloor heating in combination with heat pumps A heat pump can be used in combinations with an underfloor heating system. The efficiency of the heat pump is called the Coefficient of Performance (COP) and is the ratio between the energy usage of the compressor and amount of useful heat extracted from the condenser. The COP for a heat pump is affected by several factors, one being the temperature difference between the heat distribution and the heat source. The lower this temperature lift is the higher the COP of the heat pump will be. See Figure 1.1 for example. (Berntsson, 2000)

Variation of COP for different heat pumps with temperature lift LIFT (°C) TYPE OF HEAT PUMP 20°C 25°C 30°C 35°C 40°C 45°C 50°C 55°C 60°C Earth source (G & W) 9.26 7.15 5.8 4.8 4.15 3.6 3.2 2.9 2.6 High efficiency ASHP 7.5 5.9 4.75 3.9 3.4 3 2.25 2 1.9 Standard ASHP 4.5 3.5 2.5 1.9 1.8 1.7 1.6 1.5 1.4 Figure 1.1 COP difference with different temperature lifts with different types of heat pumps

Since an underfloor heating system operates with a lower temperature than for example a radiator heating system the temperature lift will be lower when using this system, giving the heat pump a higher COP. If a heat pump is used in combination with a heating system it is therefore more beneficial to use an underfloor heating system. 1.3 Objectives

Underfloor heating has both advantages and disadvantages in different perspectives regarding energy use, indoor climate and economy. Particularly the option to utilize the thermal mass is influence with an underfloor heating system. This thesis will investigate the existing knowledge on issue of underfloor heating and how residents with underfloor heating perceive their indoor climate by a questionnaire. It will also include indoor climate measurements and energy simulations to try to resolve important factors influencing the energy use and indoor climate by use of underfloor heating. 1.4 Limitations

This thesis has limited its research to single family houses and thereby taking away the factor of heating from others dwellings. Electric floor heating is not investigated in this study, since it is considered having to high primary energy use to be worthwhile. The underfloor heating system is only looked at as a heating system in this thesis and not as a cooling system where cold water is run through instead of hot water.

Underfloor heating- a solution or a problem Measurements and simulations made in this study are limited to two heating systems, water radiator heating systems and water underfloor heating systems. Results from simulations are based on the geographical location Helsingborg in Sweden and any conclusions based on these results may not be representative for different locations.

Underfloor heating- a solution or a problem

Underfloor heating- a solution or a problem 2 Method

In this chapter the different methods used in order to fulfil the objectives of this thesis is presented. 2.1 Questionnaire study

In order to determine how pleased residents are and how they perceive their indoor climate with underfloor heating it was decided that a questionnaire study needed to be conducted. In order to get sensible results the single family houses targeted in the study needs to fulfil different requirements. The houses could not be too old since underfloor heating is rarer in older buildings and building standards have changed. Row houses and multiple family houses should be avoided because of the heat transfer between apartments or houses. If possible the targeted houses should have the same outdoor climate and thereby be affected by climate changes in the same way. It would also be preferred if the houses had different types of heating system in order to compare the results. It was, because of previous mentioned reasons, decided that to hand out paper questionnaires directly to the houses would be the most efficient way to carry out the study. By doing it this way, houses that did not meet the requirements could be skipped and only information valuable to the study would be collected. A relatively new built residential area with a lot of single family houses would fit well, both because of logistic reasons and that the houses would share the same outdoor climate. The questionnaires were delivered with a pre-stamped envelope and a covering letter (see Appendix A) that explains how and why the study is conducted. The questionnaire used is a composition between two surveys made by Boverket (small houses and adult) and a series of made up questions that were relevant to this thesis. In order to not reveal that the study is about underfloor heating or heating systems, which could affect the residents’ answers, the headline of the questionnaire was “A few questions about your indoor climate” and also contains some questions that are not relevant to the study. In the survey (which can be seen in appendix B in Swedish) the residents answers questions on a scale from either 1-5 or 1-3 on how pleased they are with aspects of their indoor climate regarding different phenomenon, changing outdoor climate etc. The questionnaire also contains questions about which types of flooring material the house has and which types of heating systems that exists. The respondents will be able to remain anonymous or will be able to fill in their name and phone number and thereby accepting further questioning if needed. The results from the questionnaire study will be analysed and answers from houses with different heating systems will be compared, the level of satisfaction with underfloor heating in different aspects will try to be determined and the most common floor materials will affect the upcoming simulations in this thesis. Maria Park, a residential area located a few kilometres north of Helsingborg in Sweden, was chosen to be the target area of this study. It was chosen because it is a large residential area (which means a lot of potential respondents), it is relatively new built and has a lot of single family houses that does not have the same type of heating systems.

Underfloor heating- a solution or a problem A total of 400 surveys were handed out directly to the mailbox of houses in Maria Park. They were only handed out to buildings that looked to fit the requirements, houses that did not were skipped. 2.2 Indoor climate measurements

In order to get a more detailed view of how the indoor climate changes with different factors, it was decided that temperature and humidity measurements needs to be made on single family houses with water underfloor heating systems and the more traditional water radiator heating systems. Respondents from the questionnaire study with these types of heating systems will be selected and asked if they allow for measuring in their homes. The selected responders should meet the requirements mentioned in chapter 2.1. They should especially share the same outdoor climate in order to be able to be compared with each other. The purpose of doing these measurements will be to try to see how and how fast the two different systems adapts to changes in the outdoor climate, if the indoor temperature varies more with one system compared to the other and if the average temperature with an underfloor heating system is lower than with a radiator heating system. In order to collect data when the outdoor climate creates interesting conditions and to be sure that the heating systems would be turned on, the measuring period for all measured houses was set to be between the 20th March and the 10th of April (during the heating season). 2.2.1 Loggers and outdoor climate The loggers used in the measuring was Onset® HOBO® temp/RH loggers which has a margin of error of ±0.21°C for temperature and a 2.5% accuracy for relative humidity. Since ±0.21°C does not make a significant difference in these measurements it was discussed and decided that this should be ignored. The relative humidity was on the other hand corrected since 2.5% makes a significant difference in the range of the data that was collected. The logger registered values every fifth minute for both temperature and relative humidity. (Onset, 2015) The residents were instructed not to place the logger in direct sun light, on the floor or in a box or cabinet. It was recommended to place the logger in the hall or living room where the humidity from the kitchen or the bathroom affected as little as possible. Data for the outdoor climate was taken from SMHI’s measurements of Helsingborg for the time of interest. SMHI’s temperature and relative humidity measurements were given, unlike the loggers, for every hour. (SMHI, 2015) 2.2.2 Sorting of values Microsoft Excel was used to sort and analyse the measurements, all values was scanned in order to detect unrealistic values that could have been caused by residents moving the loggers. No such values were detected. Since the measurements from SMHI was given every hour and the measurements from the loggers every fifth minute the values did not enter the same rows in excel. This was problematic because diagrams that include both measurements, in order to analyse the 8

Underfloor heating- a solution or a problem results, were required. A macro was written in excel to insert eleven empty rows between every value given from SMHI and thereby matching the loggers values. The macro can be seen in Figure 2.1.

Figure 2.1 Macro used to insert eleven empty rows between every value in Excel 2.2.3 Analyses of the measured houses In order to see how well the residents perceive their indoor climate, the answers of the questionnaire study (for the measured houses) were compared with the measured data. To give a clearer view on how the buildings are used, moisture supply were calculated for each measured residences. 2.3 Simulations

Many of the possible advantages and disadvantages of having underfloor heating systems comes from the fact that the system heats up a large area and then uses this stored energy to create an even indoor climate throughout the day. It is also alleged that an underfloor heating system allows for a lower room temperature and because of that needs less energy. To try to determine if the possible advantages and disadvantages with an underfloor heating system, which is more explained in chapter 1.2.1 and 1.2.2, is correct a series of simulations will be made using Design Builder, which is an interface program for EnergyPlus. The simulated building in this study will be a 16 m times 12 m one story single family house. Two different heating systems will be used, water underfloor system and water radiator system. Different flooring materials will be used based on the results from the questionnaire study and different U-values on building components will be used in order to try to see how this affects the energy consumption and balance of the systems. 2.4 Industry knowledge and directives

To be able to determine the possible advantages and disadvantages of using an underfloor heating system and try to investigate the ones that cannot be investigated through simulations, a literature study and interviews with expert and authorities will be conducted. This study will also aim to find out the level of knowledge and what types of guidelines that exist in the building industry. The possible advantages and disadvantages found through this study are described in chapter 1.1.2-1.2.2 and the conclusions of this study will be discussed in chapter 4.

Underfloor heating- a solution or a problem

Underfloor heating- a solution or a problem 3 Results and analysis

In this chapter the results from the different studies are presented and analysed. Some discoveries and interesting results are pointed out and shortly commented but will be more discussed in chapter 4. 3.1 Questionnaire study

Off the 400 residents asked 141 responded, which is an answering rate of approximately 35%, most of them responding anonymously. 120 residences used underfloor heating and 21 used other heating systems. The results of these 141 answered questionnaires were compared and analysed using Microsoft Excel. In order to compare underfloor heating systems (shortened UFH) with other systems, answered questionnaires with underfloor heating was sorted out, these results was then compared with results from answered questionnaires with different heating system (which is referred to in this thesis as “other”). In order to analyse the results, an average of the answers is calculated and the percentile for 97.5% and 2.5% are used to see the spread of the answers. The percentile is a measure that indicates the value where the given percentage of observations in a group of observations is below, for example if the 97.5 percentile is 20, 97.5% of all values are below 20. 3.1.1 Overall satisfaction The respondents have answered questions on how satisfied or dissatisfied they are with their residence on a scale from 1-5, 1 being satisfied and 5 being dissatisfied. Underfloor heating systems are compared with other heating systems in order to try to see if this system is more satisfying.

Underfloor heating- a solution or a problem

Percentile 97.5 3

Average

2 1.90 1.84 1.78 1.80 Percentile 2.5 1.45 1.28 1

0 How satisfied How satisfied How satisfied How satisfied How satisfied How satisfied are you with are you with are you with are you with are you with are you with your residenceyour residenceyour residenceyour residence the thermal the thermal as a whole? as a whole? regarding regarding comfort in comfort in (UFH) (Other) energy use? energy use? your your (UFH) (Other) residence? residence? (UFH) (Other)

Figure 3.1 Results from the overall satisfaction questions in the survey. The higher the number on the x- axis is the more dissatisfied the responders are.

In all questions seen in Figure 3.1 residences with underfloor heating is on average slightly more satisfying than residences that use other heating systems. The spread in the answers are however greater with underfloor heating system, this shows that responders that are dissatisfied with energy use and thermal comfort of their residence are more dissatisfied if they have an underfloor heating system. This is particularly evident regarding energy use. High energy use on an underfloor heating system could indicate that the heat is wasted, either by lack of insulation or by factors that forces the system to turn on and off in order to keep the wanted indoor temperature. It could also mean that the residences with underfloor heating systems do not have a lower indoor temperature than residences with other heating methods. 3.1.2 Discomforts The respondents answered questions on how often they experience different discomforts such as draught or unsatisfying indoor temperatures. Answers were given on a scale from 1- 3, 3 being never, 2 being sometimes and 1 being often. The goal of these questions was to try to see if different discomforts are more common or less common when using an underfloor heating system and try to see if it is harder to control these types of systems.

Underfloor heating- a solution or a problem 3.1.2.1 During heating season Since the heating systems is mostly used during the heating season and since interesting conditions are in place during this time some questions are asked only for this time frame. The interesting conditions being that the solar energy is affecting the indoor climate even though it is still cold outside. On the x-axis 3 means never, 2 means sometimes and 1 means often.

Have you during the last 3 month (dec-feb) been troubled by.... 4 3 2.73 2.80 2.66 Percentile 97.5 2.45 2.43 2.35 2 Average 1 Percentile 2.5 0

Figure 3.2 Results of discomfort factors during the heating season

As seen in Figure 3.2 underfloor heating systems do not differ much from other systems regarding discomfort during heating season. Interesting is that when the respondent have problems with varying room temperatures they have more problem with underfloor heating systems than other systems even though the average is better. Draught does not appear to be more problematic in houses with underfloor heating and it is more common with high temperatures when using other systems.

3.1.2.2 During the whole year The respondents were then asked if and how frequent discomforting temperatures occur in their residence during the summer and the winter.

Underfloor heating- a solution or a problem

Are you in your residence troubled by... 4

3 2.98 3.00 2.69 2.60 2.80 2.80 Percentile 2.25 2.25 97.5 2 Average 1 Percentile 2.5 0

Figure 3.3 Survey results of discomforting indoor temperatures during summer and winter

The respondents view on discomforting temperatures during summer or winter in their residence is almost the same whether they have an underfloor heating system or not (as seen in Figure 3.3). The only difference is that underfloor heating systems have a slightly better average when it comes to uncomfortable cold temperatures during winter time. Highest discomfort is with high temperatures during summer time. The responders were asked if and how often different types of draught occurred in their residence and if and how often they experience cold floors. This is interesting since underfloor heating systems does not prevent downdraught in the same way as for example radiator heating systems.

Are you in your residence troubled by... 4 3 2.72 2.70 2.80 2.90 2.72 2.75 Percentile 97.5 2 Average 1 0 Percentile 2.5

Figure 3.4 Survey results on frequency of different discomforting factors

Underfloor heating- a solution or a problem As seen in Figure 3.4 downdraught from windows does not occur especially often in residence with underfloor heating systems, which could be a possible disadvantage of using this system, although it is more common than when using other systems. Another interesting result is that cold floors is nearly as common in underfloor heating systems as it is in other systems even though the heat radiates from the floor. To try to see if underfloor heating systems are harder to control than other systems and if the temperature varies during changes in the outdoor temperature, the respondents answered questions on how they perceive these issues.

Are you in your residence troubled by... 4 3 2.55 2.29 2.50 2 2.25 Percentile 97.5

1 Average

0 Percentile 2.5 varying room varying room difficulty to difficulty to temperatures temperatures influence room influence room during during temperature temperature temperature temperature (UFH) (other) changes outside changes outside (UFH) (other)

Figure 3.5 Results on how respondents perceive varying room temperatures and difficulty to influence the this temperature

As seen in Figure 3.5 it is more common to have varying room temperature during temperature changes outside when using an underfloor heating system. This indicates that this system is slow to adapt to changing conditions. When the respondents have difficulty to influence the room temperature they have a higher level of difficulty if they use an underfloor heating system. Despite that it is more common to have a problem with this if another system is used. 3.1.3 Flooring materials To see which flooring material that is the most common when using underfloor heating systems, the respondents answered questions on which types of flooring materials they have, both on the ground floor and upstairs floors. It is also of interest to see if the designers of the buildings prefer to use a flooring material that stores much heat or a material that stores lower amounts of heat. These results are presented in percent of how many of the residences that have a specific type of flooring material above an underfloor heating system.

Underfloor heating- a solution or a problem

100% 90% 84.2% 85.8% 80% 70% 60% 50% 40% 30% 20% 9.2% 10% 2.5% 0% PVC-/vinyl floor Wood/wood Tiled Stone parquet

Figure 3.6 Results in percentage on how common certain flooring materials above underfloor heating is on the ground floor

100% 90% 80% 70.0% 70% 60% 50% 40%

30% 20.8% 20% 14.2%

10% 0.8% 1.7% 0% Carpeted Wood/wood Tiled Stone No underfloor parquet heating upstairs Figure 3.7 Results in percentage on how common certain flooring materials above underfloor heating is on upstairs floors

From the results that is presented in Figure 3.6 and Figure 3.7 it is clear that wooden flooring and tiled flooring, often in combination (which is the reason the percent’s adds up to more than 100), is the most common flooring material when using underfloor heating systems. These two flooring materials will therefore be used and analysed in the upcoming simulations. It is approximately equally common with tiled as it is with wooden flooring and therefore the results do not answer if a heavy flooring material is more preferred than a lighter. The results also show that 70% of all respondents with underfloor heating systems do not have underfloor heating systems on the upstairs floors. This can be explained by that it takes a lot of labour to put in all the piping to have an underfloor heating system on upstairs floors, which in turn can cost more than it gives. 16

Underfloor heating- a solution or a problem 3.1.3.1 Cold floors According to the survey residents with underfloor heating systems experience cold floors nearly as much as residents without this system, which is peculiar since the heat is supplied from the floor. In order to try to find a reason for this the surveys where cold floors were a discomfort was sorted out to see which flooring material these houses have.

3.0%

Wood/wood parquet Tiled 87.9% 90.9% Stone

Figure 3.8 Flooring materials when having discomfort with cold floors and using an underfloor heating system

As seen in Figure 3.8 it is most common to have a combination of tiled flooring and wooden flooring. 82% of the houses in this study have that combination above their underfloor heating system. It is therefore hard to be sure if one material causes cold floors more than the other. It is only residents with these three flooring materials that have problems with cold floors.

3.1.3.2 Varying temperature with different flooring materials As explained in chapter 1.2.3 the flooring material can have an impact on how much the indoor temperature varies with an underfloor heating system. In order to try to see if the flooring material influences the varying indoor temperature, the respondents with this issue was sorted out and the flooring materials of this residences was compared. This is done to see if it is more or less common with varying indoor temperature with a lighter of heavier flooring material.

Underfloor heating- a solution or a problem

9.9%

Wood/wood parquet 82.9% PVC-/vinyl floor Tiled 85.6% Stone

2.7%

Figure 3.9 Flooring material when having problems with varying indoor temperature caused by changing outdoor temperature

As seen in Figure 3.9 it is slightly more common to have a heavy flooring material when having problems with varying indoor temperature, the difference is although very small. In order to investigate this further, only residence that often has problems with varying temperature (answer 3) is sorted out and their flooring materials are compared.

13.6%

Wood/wood parquet 75.0% PVC-/vinyl floor Tiled Stone 84.1%

2.3%

Figure 3.10 Flooring material when often having problems with varying indoor temperature caused by changing outdoor temperature

In Figure 3.10 the difference is clearer, it is more common with heavy flooring materials when often having problem with varying indoor temperature caused by changing temperature outdoors.

Underfloor heating- a solution or a problem 3.1.4 Wanted temperature In the survey the respondents answered on which temperature they would like to have in their residence and which temperature they experience, both for winter and summer. The average difference between these temperatures would give a result on how close the heating system is on giving the wanted temperatures, at least how close the respondents perceive it to be. Temperature difference/°C 3 2 1 Percentile 0 0.07 0.15 97.5 Winter (UFH) Summer (UFH) Winter (other) Summer (other) -1 Average -2 -1.94 -1.75 -3 Percentile 2.5 -4 -5 -6 -7 -8 -9 -10

Figure 3.11 Results on the difference between wanted and perceived indoor temperature in winter and summer

As seen in Figure 3.11 the difference in wanted and perceived indoor temperature is very low during winter time. In summer the difference is, in both underfloor heating and other systems, much larger but more when using underfloor heating. Some of the respondents using this system could even perceive temperatures more than 9°C warmer than what they would like to have. 3.2 Indoor climate measurements

In the questionnaire study the respondents could leave their name and telephone number and accept to be contacted if needed. Some respondents did that and a few of them was contacted and asked if they would allow temperature and humidity measuring in their residence. Three residences with water radiator systems and four residences with water underfloor heating systems allowed measuring.

Underfloor heating- a solution or a problem 3.2.1 Temperature measurements One of the possible advantages of underfloor heating is that it should allow a lower indoor temperature than for example radiator heating systems. In order to see if this is correct, in the measurements made for this study, an average of all logged temperatures in each residence was calculated and compared.

Figure 3.12 Results of the average temperatures of the measured residences

As seen in Figure 3.12 only “Underfloor heating 2” has a significantly lower average temperature than the residences using radiators. In the other residences the average temperature is fairly even. The percentiles give an indication that the spread of logged temperatures is larger in the residences that uses underfloor heating systems.

3.2.1.1 Distribution of logged temperatures To take a closer look on the spread and to some extent see how much the indoor temperature varies, the logged temperatures were sorted from smallest to largest and then compared.

Underfloor heating- a solution or a problem

Temperature/°C Temperature/°C 26 15 25 Radiator 1

24 10 Radiator 2 23 Radiator 3 22 5 21 Underfloor heating 1 20 Underfloor heating 2 0 19 Underfloor heating 3 18 Underfloor heating 4 17 -5 16 Outdoors (second axis) 15 -10 0 1000 2000 3000 4000 5000 6000 Figure 3.13 Variation in temperature for the measured residences

In Figure 3.13 it can be seen that the radiator systems (the line of Radiator 1 is underneath the line of Radiator 2) has a spread that is more even than the underfloor heating systems. The temperature in all residences seems to more or less follow the curve of the outdoor temperature. The underfloor heating systems have more thermal spikes, which could indicate that these systems are slower to adapt to raising outdoor temperatures or solar gains. To try to see how fast the heating system in each residence adapted to changing outdoor temperatures, the measured indoor temperature was compared with the outdoor temperature. Looking for heat peaks indoors and if they occur shortly after raising temperatures outside, also to try to see how high these peaks gets. In figure 3.14-3.20 this comparison is presented for each residence. Temperature/°C Temperature/°C 25.5 20

25 15

24.5 10 Inside Temp 24 5 Outside Temp 23.5 0

23 -5

22.5 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.14 Inside temperature for Radiator 1 compared with the outside temperature 21

Underfloor heating- a solution or a problem

Temperature/°C Temperature/°C 25.5 20

25 15

24.5 10 Inside temp 24 5 Outside Temp 23.5 0

23 -5

22.5 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.15 Inside temperature for Radiator 2 compared with the outside temperature

Temperature/°C Temperature/°C 24 20 23.5 23 15 22.5 10 Inside 22 Temp 21.5 5 21 Outside 20.5 0 Temp 20 -5 19.5 19 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.16 Inside temperature for Radiator 3 compared with the outside temperature

Temperature/°C Temperature/°C 26 20 25.5 25 15 24.5 10 Inside 24 Temp 23.5 5 Outside 23 temp 22.5 0 22 -5 21.5 21 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.17 Inside temperature for Underfloor heating 1 compared with the outside temperature

Underfloor heating- a solution or a problem

Temperature/°C Temperature/°C 24 20

23 15

22 10 Inside Temp 21 5 Outside 20 0 Temp

19 -5

18 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.18 Inside temperature for Underfloor heating 2 compared with the outside temperature

Temperature/°C Temperature/°C 26 20 25.5 25 15 24.5 10 Inside 24 Temp 23.5 5 Outside 23 Temp 22.5 0 22 -5 21.5 21 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.19 Inside temperature for Underfloor heating 3 compared with the outside temperature

Temperature/°C Temperature/°C 25 20

24 15

23 10 Inside Temp 22 5 Outside 21 0 Temp

20 -5

19 -10 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.20 Inside temperature for Underfloor heating 4 compared with the outside temperature

Underfloor heating- a solution or a problem It is no surprise that the temperature raises shortly after raising temperatures outside, the interesting, with the comparisons in Figure 3.14-Figure 3.20, is to see how fast the system adjusts its heating after these heat peaks outside. After examining these diagrams and the data behind them it seems that the underfloor heating systems is slower to adapt and therefore causes higher temperature peaks than radiator systems. To more see how the temperature differs inside the measured residences the difference between the maximum and the minimum temperature in each residence was calculated. Table 3.1 The temperature difference between the maximum and the minimum temperature for every measured day in the measured residences

Date UFH1/°C UFH2/°C UFH3/°C UFH4/°C Rad1/°C Rad2/°C Rad3/°C 20/03/2015 1.34 0.81 0.96 2.20 0.51 0.46 0.77 21/03/2015 0.86 0.62 0.69 0.76 0.82 1.03 1.01 22/03/2015 2.02 1.43 1.05 2.10 0.87 0.91 1.03 23/03/2015 1.82 1.00 1.51 2.27 0.79 0.38 1.08 24/03/2015 0.77 0.62 0.65 3.31 1.04 0.26 0.96 25/03/2015 0.41 0.40 0.45 3.70 0.91 0.29 0.57 26/03/2015 0.60 0.79 0.41 1.72 1.01 0.22 0.57 27/03/2015 1.37 0.93 0.93 1.89 0.96 0.58 0.88

28/03/2015 1.70 0.74 1.17 2.54 0.98 0.34 0.93 29/03/2015 1.41 0.74 0.62 1.75 1.35 0.22 1.17 30/03/2015 0.96 0.90 1.32 2.89 1.28 0.67 3.39 31/03/2015 0.81 1.12 0.72 0.65 1.11 0.24 1.24 01/04/2015 1.75 0.79 1.58 2.13 1.28 0.41 1.27 02/04/2015 2.86 1.55 1.65 2.09 0.94 0.50 1.27 03/04/2015 2.52 4.63 1.58 2.62 1.15 0.74 1.15 04/04/2015 2.47 2.19 1.73 2.81 1.08 0.77 1.41 05/04/2015 2.67 1.43 3.37 2.43 0.70 1.04 1.55 06/04/2015 3.59 2.05 1.42 2.98 2.07 2.00 2.01 07/04/2015 1.39 1.00 0.84 1.58 1.71 0.24 1.08 08/04/2015 1.71 2.02 1.82 3.05 1.49 0.67 1.15 09/04/2015 1.66 1.55 2.35 3.48 1.28 0.53 1.44

Average: 1.65 1.30 1.28 2.33 1.11 0.60 1.23

Underfloor heating- a solution or a problem As seen in Table 3.1 it is more common to a have larger temperature difference between the daily maximum and minimum indoor temperatures when using an underfloor heating system. When examining Figure 3.18 it looks like Underfloor heating 2 should have a less varying indoor temperature than the rest of the residences but it has a peak on the third of April that affects its average in Table 3.1. If this date was to be taken away the average daily temperature difference would be 1.13°C, which is as good as for a residences using radiator heating.

3.2.1.2 Influence of the outside temperature In order to closer investigate how much the outside temperature influences the inside temperature, diagrams with the indoor temperature as a function of the outside temperature were made. With the help of Excel a trend line and an equation that shows the connection between the two variables were added.

Temperature/°C 26 25.5 25 24.5 y = 0.1054x + 22.526 24 R² = 0.1947 23.5 23 22.5 22 21.5 Temperature/°C -10 -5 0 5 10 15 20

Figure 3.21 The inside temperature as a function of the outside temperature in Underfloor heating 1

As seen in Figure 3.21 there is, unsurprisingly, a connection between the outdoor and indoor temperature. The interesting being the factor in front of x (for future references called k) in the equation, the closer this factor k is to one the larger the connection is between the outside and inside temperature. The coefficient of determination (R²) describes how well one variable describes the other, in this case how well the outdoor temperature describes the indoor. If R² is between minus one and zero the connection is negative, if it is zero there is no connection and if it is between zero and one the connection is positive. This analysis was made for all measured residences and the resulting coefficients are presented in the table below.

Underfloor heating- a solution or a problem Table 3.2 The connection variables for the indoor and outdoor temperatures in the measured residences

k R² Average Average k R² Underfloor heating 1 0.1054 0.1947 Underfloor heating 2 0.0320 0.0317 Underfloor heating 3 0.0527 0.0526 0.0842 0.1128 Underfloor heating 4 0.1467 0.1720 Radiator 1 0.0286 0.0399 Radiator 2 0.0145 0.0195 0.0300 0.0833 Radiator3 0.0467 0.1904 It seems like the outdoor temperature has a slightly larger influence on the indoor temperature when using underfloor heating systems. The average coefficients k and R² are larger for the residences with underfloor heating systems.

3.2.1.3 Comparison between the two measured systems In order to see how the two different systems compare with each other, interesting values such as average temperature, maximum and minimum temperature, for the measured temperatures of all residences with underfloor heating was compared with the values of all residences with radiator heating systems. Table 3.3 Temperature comparisons between the two systems

Underfloor heating Radiators Average temperature/°C 21.81 23.35 Standard deviation/°C 1.556 0.459 Maximum temperature/°C 25.525 25.113 Percentile 95/°C 24.026 24.120 Percentile 75/°C 22.848 23.597 Percentile 50/°C 22.178 23.328 Percentile 25/°C 20.674 23.117 Percentile 5/°C 19.08 22.853 Minimum temperature/°C 18.604 21.036 The standard deviation is a distribution measurement on how the values are distributed around the average value. As seen in Table 3.3 the average temperature is lower in the residences with underfloor heating but the standard deviations is larger, which indicates that temperatures when using this system varies more. 26

Underfloor heating- a solution or a problem 3.2.2 Humidity measurements In order to see if there is any differences in humidity levels when using underfloor heating systems or radiator heating systems the same comparisons made with temperature in chapter 3.2.3 was made for the measured humidity.

Relative humidity/% 50

97.5 percentile 40 Average 38.40 37.79 2.5 percentile 36.54 35.44 35.81 35 34.87

31.22 30

25 Radiator 1 Radiator 2 Radiator 3 Underfloor Underfloor Underfloor Underfloor heating 1 heating 2 heating 3 heating 4

Figure 3.22 Results of the average relative humidity in the measured residences

In Figure 3.22 it is showed that there is no significant difference in the average relative humidity levels when using underfloor or radiator heating systems. The spread of the levels differs a lot from residence to residence and will therefore be further investigated. To try to see if there is more spread in relative humidity levels with the different heating systems, the measured values was sorted from smallest to largest and then compared.

Underfloor heating- a solution or a problem

Relative Relative humidity/% humidity/% 60 100 Radiator 1

55 Radiator 2 90 50 Radiator3 80 45 Underfloor heating 1 40 70 Underfloor heating 2 35 Underfloor 60 heating 3 30 Underfloor 50 heating 4 25 Outside (second axis) 20 40 0 2000 4000 6000 Figure 3.23 Variation in relative humidity for the measured residences

Figure 3.23 show that the residences using radiator heating systems have more high values of relative humidity, the residences with underfloor heating have more even relative humidity levels. To try to see how the relative humidity changes with the indoor temperature, these values were compared and analysed. This should give an indication of when the high level of relative humidity occurs.

Temperature/°C Relative humidity/% 25.5 50

25 45 Indoor 24.5 40 temp 24 Indoor 35 RH 23.5

23 30

22.5 25 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.24 Indoor relative humidity for Radiator 1 compared with the indoor temperature

Underfloor heating- a solution or a problem

Temperature/°C Relative humidity/% 25.5 50

25 Indoor 24.5 40 temp 24 Indoor RH 23.5 30

22.5 20 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.25 Indoor relative humidity for Radiator 2 compared with the indoor temperature

Temperature/°C Relative humidity/% 24 55 23.5 50 23 22.5 45 Indoor temp 22 40 21.5 Indoor 21 35 RH 20.5 30 20 25 19.5 19 20 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.26 Indoor relative humidity for Radiator 3 compared with the indoor temperature

Temperature/°C Relative humidity/% 26 40 25.5 25 24.5 Indoor 24 temp 23.5 30 23 Indoor RH 22.5 22 21.5 21 20 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.27 Indoor relative humidity for Underfloor heating 1 compared with the indoor temperature

Underfloor heating- a solution or a problem

Temperature/°C Relative humidity/% 24 50

22 Indoor temp 21 40 Indoor 20 RH

18 30 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.28 Indoor relative humidity for Underfloor heating 2 compared with the indoor temperature

Temperature/°C Relative humidity/% 26 45 25.5 25 40 24.5 Indoor 24 temp 23.5 35 23 Indoor 22.5 RH 30 22 21.5 21 25 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.29 Indoor relative humidity for Underfloor heating 3 compared with the indoor temperature

Temperature/°C Relative humidity/% 25 55

24 50 45 23 Indoor 40 temp 22 35 Indoor 21 30 RH 20 25 19 20 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.30 Indoor relative humidity for Underfloor heating 4 compared with the indoor temperature

Underfloor heating- a solution or a problem The relative humidity is the amount of humidity (in g/m³) in the air divided by the amount of humidity the air can carry (in g/m³) and the higher temperature of the air, the more humidity it can carry. This should, if no other factors influences mean that if the indoor temperature increases the relative humidity should decrease. As seen in Figure 3.24-Figure 3.30 this is the case on some occasions but not all the time, which than means that there is other factors influencing the indoor relative humidity. Since the indoor temperature affects the indoor relative humidity it can be seen that residences with a more even temperature has a more even relative humidity. The peaks and drops in relative humidity often appear with changes in the temperature. Another factor that can affect the indoor relative humidity is the outdoor relative humidity, in order to see how this affects these two relative humidity’s was compared. Relative Relative humidity/% humidity/% 50 100 45 90 Indoor 40 80 RH 35 70 Outdoor RH 30 60 25 50 20 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.31 Relative humidity for Radiator 1 compared with the outdoor relative humidity

Relative Relative humidity/% humidity/% 50 100 45 90 40 80 Indoor RH 35 70 Outdoor 30 60 RH 25 50 20 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.32 Relative humidity for Radiator 2 compared with the outdoor relative humidity

Underfloor heating- a solution or a problem

Relative Relative humidity/% humidity/% 60 100 55 90 50 Indoor 45 80 RH 40 70 Outdoor 35 60 RH 30 50 25 20 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.33 Relative humidity for Radiator 3 compared with the outdoor relative humidity

Relative Relative humidity/% humidity/% 40 100 38 36 90 34 Indoor 80 RH 32 30 70 Outdoor 28 RH 26 60 24 50 22 20 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.34 Relative humidity for Underfloor heating 1 compared with the outdoor relative humidity

Relative Relative humidity/% humidity/% 50 100 48 46 90 Indoor 44 80 RH 42 40 70 Outdoor 38 RH 36 60 34 50 32 30 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.35 Relative humidity for Underfloor heating 2 compared with the outdoor relative humidity

Underfloor heating- a solution or a problem

Relative Relative humidity/% humidity/% 50 100 90 45 Indoor 80 RH 40 70 35 Outdoor 60 RH 30 50 25 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.36 Relative humidity for Underfloor heating 3 compared with the outdoor relative humidity

Relative Relative humidity/% humidity/% 60 100 55 90 50 Indoor RH 45 80 40 70 Outdoor 35 60 RH 30 25 50 20 40 19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00 Figure 3.37 Relative humidity for Underfloor heating 4 compared with the outdoor relative humidity

As seen in Figure 3.31-Figure 3.37 the indoor relative humidity curve mostly follows the curve of the outdoor relative humidity in all residences, with an even difference. In some cases the relative humidity indoors is high even through the outdoors relative humidity is relatively low, this could be due to the presence of people, which produce both heat and moisture.

3.2.2.1 Comparison between the two measured systems In order to see how the two different systems compare with each other, interesting values such as average humidity, maximum and minimum humidity, for the measured temperatures of all residences with underfloor heating was compared with the values of all residences with radiator heating systems.

Underfloor heating- a solution or a problem Table 3.4 Relative humidity comparisons between the two systems

Underfloor heating Radiators

Average relative humidity/% 35.57 35.93

Standard deviation 4.29 3.59

Maximum relative humidity/% 51.85 55.83

Percentile 95 43.16 41.57

Percentile 75 38.27 37.89

Percentile 50 35.42 36.02

Percentile 25 32.57 33.89

Percentile 5 29.11 29.98

Minimum relative humidity/% 24.54 21.66

As seen in Table 3.4 the relative humidity does not differ much between the two systems. Which type of heating system that is used probably does not affect the indoor relative humidity as much as other factors does, for example the outdoor relative humidity.

3.2.2.2 Influence of the outside relative humidity In order to see how much the outside relative humidity influences the indoor, the same comparison that was made for temperature in chapter 3.2.1.2 was made for the relative humidity. As seen in Table 3.5 there is a clear connection between the outdoor and indoor relative humidity. It does not seem to matter which heating system that is used, there is probably other factors in the building that influences this more.

Underfloor heating- a solution or a problem Table 3.5 The connection variables for the indoor and outdoor relative humidity in the measured residences

k R² Average Average k R² Underfloor heating 1 0.0487 0.0608

Underfloor heating 2 0.0525 0.043 0.0932 0.1359 Underfloor heating 3 0.0736 0.1725 Underfloor heating 4 0.1981 0.2673 Radiator 1 0.0881 0.1005

Radiator 2 0.0819 0.1091 0.1057 0.1314 Radiator3 0.1471 0.1845

3.2.3 Analysing the measured residences In order to see how well the responders perceive their indoor climate the questionnaire answers for the measured residences was compared with the measured data. The added excess moisture was also calculated to try to see how these measured residences were used during the measuring period.

3.2.3.1 Comparing with the questionnaire answers Since humans produce both heat and moisture it is interesting to see if and how much the amount of residents influences the temperature and relative humidity. It is also interesting to see how accurate the responders are with their perceived temperature and how close the real temperature is to the wanted. Table 3.6 Number of residents, the perceived and wanted temperature of the responders compared with the average temperature and relative humidity in the measured residences

Residents Average Average relative Perceived temperature Wanted temperature humidity (%) during winter (°C) temperature (°C) during RAD1 2 23.50 35.44 21 winter21 (°C) RAD2 4 23.33 35.81 20 20 RAD3 3 22.03 36.54 22 24 UFH1 2 23.00 31.22 21 21 UFH2 4 19.49 37.79 20 20 UFH3 4 22.41 34.87 20 20 UFH4 5 22.34 38.40 23 23

Underfloor heating- a solution or a problem As seen in Table 3.6 it is not safe to say that more residents will lead to higher average temperature or relative humidity, even if this would be logical. There are many other factors that influence these results, such as size of the house and ventilation. The perceived temperature in the residences is often lower than the measured averages, the exceptions being UFH2 and UFH4.

2 RAD1 RAD2 RAD3 UFH1 1 UFH2 UFH3 UFH4

0 High Varying Too cold during Too hot during Varying Difficulty to affect temperatures temperatures winter winter temperature with the temperature during heating during heating changing outdoor season season temperature

Figure 3.38 Questionnaire study answers from the measured residences. The scale on the y-axis describes how often discomforts occur, 3 being never and 1 being often.

As seen in Figure 3.38 the residents in the measured residences do not experience high levels of discomforts during the heating season, with the exception of UFH4, which matches the results from the measurements.

3.2.3.2 Moisture supply In order to calculate the moisture supply for the measured buildings the following formulas were used:

(1) 푣 = 4.7815706 + 0.34597292 ∙ 푡 + 0.0099365776 ∙ 푡2 + 0.00015612096 ∙ 푡3 + 1.9830825 ∙ 10−6 ∙ 푡4 + 1.5773396 ∙ 10−8 ∙ 푡5 푣 = 푠푎푡푢푟푎푡𝑖표푛 푣푎푝표푟 푐표푛푡푒푛푡/(𝑔/푚3) 푡 = 푠푎푡푢푟푎푡𝑖표푛 푡푒푚푝푒푟푎푡푢푟푒 𝑖푛 ℃

(2) 푣푖 = (푟/100) ∙ 푣 푟 = 푟푒푙푎푡𝑖푣푒 ℎ푢푚𝑖푑𝑖푡푦/(%) 3 푣푖 = 푣푎푝표푟 푐표푛푡푒푛푡 𝑖푛푑표표푟/(𝑔/푚 )

Underfloor heating- a solution or a problem

(3) 푚 = 푣푖 − 푣표 푚 = 푚표𝑖푠푡푢푟푒 푠푢푝푝푙푦/(𝑔/푚3) 3 푣표 = 푣푎푝표푟 푐표푛푡푒푛푡 표푢푡푑표표푟/(𝑔/푚 )

The average moisture supply for the measured residences during the measured time period is presented in Table 3.7. As seen there is no significant difference between the two systems moisture supply averages, but the underfloor heating system seems to vary more between the different houses. Table 3.7 Average moisture addition for the measured residences during the measured period

Radiator 1 6.12 g/m³

Radiator 2 6.12 g/m³

Radiator3 5.73 g/m³

Underfloor heating 1 5.05 g/m³

Underfloor heating 2 4.98 g/m³

Underfloor heating 3 5.56 g/m³

Underfloor heating 4 6.28 g/m³

Radiator average 5.99 g/m³

Underfloor heating 5.47 g/m³ average

In Figure 3.39 the distribution of the moisture addition are presented. Again it could be said that the residences using underfloor heating varies more from each other than the residences using radiator systems. This again is an indication that installing and using underfloor heating systems correctly seems to be harder than for radiator systems.

Underfloor heating- a solution or a problem

v/(g/m³) 12

10 Radiator 1 Radiator 2 8 Radiator3 6 Underfloor heating 1 Underfloor heating 2 4 Underfloor heating 3 2 Underfloor heating 4

0 20/03/2015 00:00 10/04/2015 00:00

Figure 3.39 The distribution of the moisture supply in the measured houses. 3.3 Simulations

To try to see if the energy use in a single family house is lower when using underfloor heating systems than when using radiator heating systems, how the floor material affects the energy use and if the thermal storage is more optimised with underfloor heating a series of simulations was conducted. Since wood/wood parquet and tiled flooring was the most common materials in the questionnaire study these materials was used in the simulations. In order to see if there is a difference between the two systems when having a good insulated building or a bad insulated building simulations was done for both. The buildings simulated are identical, only interesting parameters was chanced and these are presented in Table 3.3.8 Table 3.3.8 The different properties of the simulated buildings

Good building Bad building

Wall U-value/ (W/(m²K)) 0.1 0.35

Roof U-value/ (W/(m²K)) 0.1 0.25

Slab insulation U-value 0.149 0.238 (W/(m²K))

Slab insulation thickness/ 250 141 (mm)

Windows U-value/ (W/m²) 0.774 1.987

Underfloor heating- a solution or a problem Well-insulated buildings are (in the diagrams) shortened with Good, bad insulated buildings are shortened by Bad. Radiator systems are shortened with RAD and underfloor heating systems with UFH. 3.3.1 Energy simulations To see if the energy used to heat a single family house is lower when using underfloor heating systems than radiator heating systems energy simulations was made with the two different heating systems and two different flooring materials. A possible advantage of the underfloor heating system is that it allows for a lower indoor temperature, therefore the simulations was made for 16°C, 18°C, 20°C, 22°C and 24°C indoor temperature. Energy/ (kWh/year/m²) 190

170

150 Good UFH Wood 130 Good RAD Wood

110 Good UFH Tiles Good RAD Tiles 90

50 16°C 18°C 20°C 22°C 24°C

Figure 3.40 Simulated annual energy use for a good insulated single family house with different heating systems and flooring materials

In Figure 3.40 the energy needed to heat a well-insulated single family house to different temperatures, with different heating methods and different flooring materials over one year is shown. Underfloor heating with tiles as flooring material is always the most energy efficient heating system, regardless on the indoor temperature. Radiators with tiled flooring use less energy than underfloor heating with wood/wood parquet this could be because of the larger thermal storage capacity of the tiled flooring.

Underfloor heating- a solution or a problem

Energy/ (kWh/year/m²) 250 230 210 190 Bad UFH Wood 170 Bad RAD Wood 150 Bad UFH Tiles 130 110 Bad RAD Tiles 90 70 50 16°C 18°C 20°C 22°C 24°C

Figure 3.41 Simulated annual energy use for a bad insulated single family house with different heating systems and flooring materials

In Figure 3.41 the energy needed to heat a badly insulated single family house to different temperatures, with different heating methods and different flooring materials over one year is shown. Although the slab has little insulation the underfloor heating system is more energy efficient than the radiator system, even if the radiator system uses tiled flooring and the underfloor heating system uses wood/wood parquet. 3.3.2 Thermal mass In order to see how big of an impact the thermal mass has on the two systems, energy simulations with different thickness (to represent thermal storage) on the flooring material was made. This was done to try to see if underfloor heating systems use the thermal mass of the floor better than radiator systems. Because the tiled flooring had the lowest energy use this material was used in the simulations and since the indoor temperature is not relevant for the results of the thermal mass an indoor temperature of 20°C was used.

Underfloor heating- a solution or a problem

Energy/(kWh/ year) 25500 25400 25300 25200 Good UFH Tiles 25100 Good RAD Tiles 25000 24900 24800 24700 20mm 30mm 40mm 50mm 100mm Figure 3.42 Results for energy use with different flooring thicknesses in a well-insulated house

It clearly shows in Figure 3.42 that the yearly energy needed to heat the building gets lower the more thermal storage that is available in the floor. Since the house with underfloor heating already has lower energy use it is hard to see if this system utilizes the thermal mass better than a radiator system. To try to find this out a second comparison was made, where the energy needed for 20mm flooring material were subtracted from the other thicknesses. This allows too see how well the different systems utilize added thermal storage, regardless from the difference in energy use.

Energy/(kWh/ year) 300 242 250 223 200 Good UFH Tiles 150 Good RAD Tiles 113 104 100 79 71 41 50 37

0 30mm 40mm 50mm 100mm Figure 3.43 Differences in energy use with different flooring thicknesses in a well-insulated house

As Figure 3.43 illustrates there is a difference in how well the systems utilizes thermal mass in the floor, the underfloor heating system takes slightly more advantage of the added mass than the radiator system. To see if amount of insulation has an impact on the above presented results the same comparisons was made for a house that is badly insulated. The interesting point being that more heat can be lost through the foundation.

Underfloor heating- a solution or a problem

Energy/(kWh/ year) 31000

30500

30000 Bad UFH Tiles 29500 Bad RAD Tiles 29000

28500

28000 20mm 30mm 40mm 50mm 100mm Figure 3.44 Results for energy use with different flooring thicknesses in a badly-insulated house

Energy/(kWh/ year) 250 197 190 200

150 Bad UFH Tiles Bad RAD Tiles 100 88 84 58 57 50 30 29

0 30mm 40mm 50mm 100mm Figure 3.45 Differences in energy use with different flooring thicknesses in a badly-insulated house

Figure 3.44 and Figure 3.45 matches the previous results with that the underfloor heating system benefits more from added thermal storage in the floor than the radiator system. The difference between the two systems ability to utilize the thermal mass is however smaller with a badly-insulated house.

Underfloor heating- a solution or a problem 4 Discussion

4.1 Industry knowledge

The knowledge on how to use and install an underfloor heating system in the building industry seems to be quite good but it might not be as well-known as one would like. In any case it is not hard to find information on the subject. On the other hand this information often comes from manufacturers of the system and of course makes the underfloor heating system look like the ideal heating method. The Swedish Energy Agency, the Swedish Consumer Agency, the National Housing Board and Formas have in collaboration created a writing called “Grundtips för golvvärme” (Boverket, 2015) (Basic tips for underfloor heating) and in this writing it is stated what you should look out for when installing this kind of system. They recommend that 250 millimeters of insulation is used underneath the floor heating and states that the goal of using underfloor heating is to lower the indoor temperature. To lower the indoor temperature is according to this writing a prerequisite in order to save energy. Anyone who wants to install or have underfloor heating systems can easily obtain this information but one can only hope that they do. The possible advantages and disadvantages found through the literature study and interviews with experts on the subject can be seen in chapter 1.2.1 and 1.2.2. One possible disadvantage is that since such a large area is heated there could be a risk that the system would overheat. It would thereby not be suited for use in for example passive houses that are well-insulated. In order for this to be true the underfloor heating systems needs to be applied underneath the entire floor or at least most of it. It has through this study come to the writers’ knowledge that passive houses with underfloor heating systems are being build, where only the floor area close to the walls are fitted with underfloor heating. This allows for a smaller area to be heated and should prevent the system from overheating. How well this works is still not known to the author of this thesis but it is regardless an attempt to address this disadvantage. 4.2 Questionnaire study

Figure 3.1 does not show that, even with the advantages of the hidden underfloor heating system, residences with this system are more satisfied than residences with other heating methods. A reason for that can be found in the same figure. If a resident is dissatisfied from a thermal comfort point of view, it is more so if using underfloor heating. The same goes for the respondents’ perception of their residence energy use. This raises the suspicion that if an underfloor heating system is not installed or used correctly it could be a bad choice. With that said the respondents using underfloor heating is on average just as satisfied with the thermal comfort and energy use as respondents with other systems. This can be interpreted as if an underfloor heating system is installed and used correctly it is at least as satisficing as other systems regarding thermal comfort and energy use and more satisfying as a whole. The most important when investigating heating systems is to investigate how it works during the heating season. Since this is the time of year when the system is in operation, the solar gains can affect the indoor climate even if it is still cold outside and draught occur

Underfloor heating- a solution or a problem more distinctly during this period. In the questionnaire study the respondents were asked if they had perceived problems with draught, too high room temperatures or varying room temperatures during December to February. To have discomforting high temperatures is on average less common with underfloor heating systems during this period, if too high temperatures occur it is also more frequent when using other systems. If the respondents were troubled by varying room temperature it is more frequent with underfloor heating systems during this period but more common to occur if another system is used. Draught from windows in buildings using underfloor heating systems is not more common than when using other systems, this might be surprising since underfloor heating does not prevent draught. The answer probably lies in that the residences investigated in this study was relatively new and was equipped with good windows that prevents downdraught. At least the study proves that if you have an underfloor heating system you do not necessarily have problems with downdraught. A risk of using an underfloor heating system was that it is more common to overheat and create high indoor temperatures than other systems. This does not seem to be the case, at least not in this study. It is actually perceived more common with overheating during the heating season with other heating methods. On the other hand the respondents with underfloor heating perceive to a more varying room temperatures. As mentioned before underfloor heating can have problems adjusting to changing conditions since there is a lot of stored heat in the foundation, this is slightly more true if the residence have a heavy flooring material, as shown in chapter 3.1.3.2. Another reason could be how the system is controlled. If the system is not controlled with an energy efficient thermostat and only measure the temperature in the floor it will not be able to adapt quick enough if the indoor temperature rises. The ability to influence the room temperature is on average perceived to be easier with underfloor heating but if it is perceived to be hard it is harder with this system. This could also be explained by not using energy efficient thermostats. It is more common than not that if the respondent is dissatisfied the respondent is more dissatisfied if they use underfloor heating systems. This could be because this system requires more from the rest of the building, it is also a newer system and it seems like the knowledge in the industry and of the residents is not as well-known as for example more traditional heating systems. Therefore it could be that this lack of knowledge leads to badly installed systems that are not in harmony with the rest of the building. Despite that it seems that it is more common that the underfloor heating system is installed and used correctly and that the residents with this system is on average more pleased than residents with other systems. An interesting result from the questionnaire study was that residents with underfloor heating experience cold floors just as much as residents with other systems despite the fact that the heat is supplied from the floor. One way to explain this could be that it is more common with flooring materials that is perceived to be colder such as stone or tiles when having an underfloor heating system. As shown in chapter 3.1.3.1 it is hard to prove that this would be the reason since wooden flooring and tilled flooring is equally common. Another way to explain this could be with the fact that residents that have underfloor heating expect their floors to be warmer than residents with other systems. If the system then is turned off, because the indoor temperature is satisfying, the residents could be more displeased with the temperature of the floor since they expect it to be warmer.

Underfloor heating- a solution or a problem It is absolutely most common with tiled or wooden flooring when using underfloor heating, which shows that the fact of using insulating materials like carpeting above the system is well-known to be a bad idea. Since tiled and wooden flooring is equally common it is difficult to say which material that is preferred by the designers of the residences. It could also be hard to control the choice of flooring material since it has a big impact on the appearance of the room. The difference between the perceived temperatures and the wanted temperatures is during winter very small regardless of which system that is being used. Despite that the respondents with underfloor heating experience less discomforting low temperatures during this period. Since this probably is the most important aspect of a heating system it is a good result for the underfloor heating system. In summer the difference is much higher in all systems, that this should have anything to do with which heating system the respondents have is unlikely. Hopefully the heating system is turned off during summer. It seems that underfloor heating systems if used and installed correctly is in most cases more satisfying than other heating systems. 4.3 Indoor climate measurements

It is claimed by authorities that lowering the indoor temperature is required in order to save energy with an underfloor heating system. It is therefore interesting that in the measured houses it is only one (Underfloor heating 2) out of four residences with underfloor heating that has an average temperature which is significantly lower than for the once using radiator systems. This would then mean that the three other residences with underfloor heating use more energy than the once using radiator systems. It could be that the residence with the low temperatures is the only measured residence with a properly working underfloor heating system. It could also be that the residents in the three other houses does not know how to control the heating system or believes/wants the indoor air temperature should/to be this high. Either way it is a result that speaks against the use of underfloor heating systems. On the other hand measurements should be performed in more houses to ensure this finding. The ability for the different systems to adapt to changing conditions is worse with the underfloor heating systems than it is with radiator systems with exception of Underfloor heating 2. Even if this residence has on one occasion a very high peak in temperature (which could have been caused by uncontrollable circumstances) it has the steadiest temperatures of the measured residences. It is the complete difference with Underfloor heating 4 where the indoor temperature varies very much even though it is the same kind of system. This indicates that the comfort provided by an underfloor heating system can vary very much depending on the residence and/or the residents. Changes in indoor temperature mostly occurs quickly after changes in the outdoor temperature, the houses with radiator systems adapts faster and stops heating quicker than the underfloor heating systems. This can be because of the thermal storage in the foundation which is more used when using underfloor heating systems and creates a more uneven temperature and higher peaks in the indoor temperatures. Neither system seems to have problems when the outdoor temperature drops. One could think that the underfloor heating system should control drops in the outdoor temperature better because of the thermal storage even if this does not show in the measured indoor temperatures. It could be that the radiators is faster to detect the falling temperatures

Underfloor heating- a solution or a problem and therefore starts heating faster than the underfloor heating system, it would then use more energy but keeps the temperature steady. The average relative humidity of the measured residences does not differ much when using underfloor heating systems or radiator systems, the exception being Underfloor heating 1 which has a lower average than the rest of the residences. It is surprising that Underfloor heating 2 do not have a higher average relative humidity since it also has lower average temperature and that the air therefore can carry less moisture. The reason for this could be that there is less residents in this house, which leads to less moisture and heat production. It could also be that this house and heating system is better built and/or controlled than the others and therefore perform better. The latter probably being the most likely one. Even if their lives less people or not in this residence it is adapted for the situation and is an indication that underfloor heating systems can have a lower indoor temperature that is steady and probably need less energy than radiator heating systems. As seen in the results of the humidity measurements the outdoor relative humidity has a higher impact on the indoor humidity than the indoor temperature does. When the indoor temperature rises it is common in the measurements that the relative humidity does too, which as previously explained means that there is another factor involved. The presence of people is probably that factor. Using underfloor or radiator heating systems does not seem to affect the indoor relative humidity significantly, at least they do not affect it in different ways. There are probably other aspects in the building construction that affect the indoor relative humidity levels more. 4.4 Simulations

According to information gathered in the literature study it is required to lower the indoor temperature in order to decrease the energy use when using underfloor heating systems. As seen in simulation results in chapter 3.3.1 this is not the case when comparing underfloor heating with radiator systems, even if the indoor temperature is set on 24°C the underfloor heating system has a lower annual energy need than the radiator system. As stated in chapter 1.2.1 underfloor heating systems should allow an indoor temperature 2-3°C lower than when using a radiator system. That would then mean that if a radiator system has a heating set point on 22°C the underfloor system should allow 20°C.

Underfloor heating- a solution or a problem

Energy difference/(kW h/year) 8000 6787 7000 6644 6000 5000 4000 3325 3431 3000 2000 1000 0 Well-insulated Well-insulated Badly-insulated Badly-insulated with wooden with tilled flooring with wodden with tilled flooring flooring flooring

Figure 4.1 Difference in annual energy use for radiator (22°C) and underfloor heating (20°C)

When comparing the annual energy use of these cases there is (as shown in Figure 4.1) a grave difference between the two systems. According to the results from Design builder the underfloor heating system would only need 87% for a well-insulated house and about 81% for a badly-insulated house of the energy that is needed for the radiator system. This result speaks against the belief that underfloor heating systems would not be suited for well- insulated houses and implies that this system is energy efficient. It seems like, according to Design builder, that underfloor heating is a superior heating method in all conditions that was tested in this study. Results from simulations does not necessary reflect the reality and there is of course a chance that Design builder is exaggerating the impact of underfloor heating systems. Another aspect could be that in the simulations the underfloor heating system works and is used as intended, which may not be the case in real houses. The human factor seems to have a big impact on how well the heating systems work and it seems like the knowledge on how to control an underfloor heating system is not as well-known as for other heating systems. As seen in Figure 3.5 residents that have problems influencing the heating systems have more problems when using an underfloor heating system. It could be that this kind of systems is harder to control since there are more factors that can influence the control of the system. It could also be that it, compared to other systems, requires more knowledge to install correctly and that this knowledge is not always known by the workers installing it. Since it is on average (according to the respondents) easier to influence the room temperature with underfloor heating systems it seems like the latter explanation is the most correct one. When it comes to the utilization of thermal mass the underfloor heating systems seems to be better than the radiator system, this is no surprise since underfloor heating heats a larger volume of potential heat storage. It does not seem like the indoor temperature drops or varies more because of lack of thermal storage with an radiator system, this can be explained by that radiator systems is quick to adapt to changing conditions and therefore starts heating to avoid changing indoor temperature. This does that the radiator systems

Underfloor heating- a solution or a problem needs more energy compared to an underfloor heating system (as seen in chapter 3.3.2). The difference in the ability to utilize the thermal storage between the two systems is lower with a badly-insulated house. This is because the stored heat escapes through the foundation and that the underfloor heating systems’ radiated heat can be wasted the same way. It is not tested in this thesis how the different systems would perform if there is zero insulation in the foundation since this hopefully would not be the case in reality. If using a heat pump in combination with the heating system it is possible to lower the energy need of the system. It is even more efficient if using underfloor heating since the temperature lift is lower with this system, which leads to a higher COP on the heat pump.

Underfloor heating- a solution or a problem 5 Conclusions

 Residents with underfloor heating systems are on average more pleased with the energy use, the thermal comfort and their residence as a whole compared with residents with other heating methods.  Discomforting high temperatures and varying temperatures is perceived to be less common during the heating season with underfloor heating systems than other systems. Draught is perceived to be slightly more common during this time period.  It is perceived that too cold temperatures during the winter period occur more often when not using underfloor heating. The perceived temperature during winter when using an underfloor heating system is very close to the wanted temperature.  Varying room temperatures during temperature changes outside is perceived to be common with underfloor heating, the reason for this is the utilization of thermal mass which creates a delay before the system stops heating the room. Despite that it is perceived to be easier to influence the room temperature when using this system compared to others.  Wood/wood parquet and tiled flooring is the most common flooring materials when using underfloor heating. Residents with heavy flooring materials that store a lot of heat have more often problems with varying indoor temperatures.  An underfloor heating system can lower the indoor temperature and thereby have a lower energy need than other systems. For this to be true the system has to be installed and controlled properly, which is not always the case.  Residences with underfloor heating systems have a more varying indoor temperature than residences with radiator heating systems, according to the measuring study in this thesis.  Changing outdoor temperatures have a greater influence on the indoor temperature when using underfloor heating systems compared to radiator heating systems.  The utilization of thermal storage helps to lower the energy need when using underfloor heating system during the heating season. This system also utilizes added thermal storage better than radiator systems.

Underfloor heating- a solution or a problem

Underfloor heating- a solution or a problem 6 Future work

 In order to see if the conclusions in this thesis are accurate it would be interesting to see questionnaire studies and measurements from other locations.  More research on heating systems in combination with heat pumps or solar collectors would be interesting to see, since this could change which systems that is the more energy efficient.  Different energy supplies could influence the energy efficiency of the system, testing this would therefore be important.  Since the main heating systems in this thesis were underfloor heating and radiator systems it could be interesting to see comparisons with other systems.

References

A.K. Athienitis and Y. Chen, 2009. The effect of solar radiation on dynamic thermal performance of floor heating systems. [Online] Available at: http://www.sciencedirect.com/science/article/pii/S0038092X00000529 [Accessed 06 10 2015] Berntsson, 2000. Heat source-technology, economy and environment. Available at: http://www.sciencedirect.com/science/article/pii/S0140700701000342 [Accessed 20 05 2015] Betsi, 2009. Enkätundersökning om boendes upplevda inomhus miljö och ohälsa. Boverket. [Online] Available at: http://www.boverket.se/sv/om-boverket/publicerat-av- boverket/publikationer/2009/enkatundersokning-om-boendes-upplevda-inomhusmiljo-och- ohalsa-/ [Accessed 06 10 2015] Betsi, 2009. Statistiska urval och metoder i Boverkets projekt Betsi. [Online] Available at: http://www.boverket.se/sv/om-boverket/publicerat-av- boverket/publikationer/2010/statistiska-urval-och-metoder-i-boverkets-projekt-betsi/ [Accessed 06 10 2015] Boverket, 2015. Grundtips för golvvärme. [Online] Available at: http://www.boverket.se/globalassets/publikationer/dokument/2002/grundtips_for_golvvarm e.pdf [Accessed 20 05 2015] Boverket, 2008. Enkät småhus. [Online] Available at: http://www.boverket.se/contentassets/83d8355da8a64114b1c5ab87cc6105b6/betsi- smahus.pdf [Accessed 06 10 2015] Boverket, 2008. Enkät ungdom. [Online] Available at: http://www.boverket.se/contentassets/83d8355da8a64114b1c5ab87cc6105b6/enkat_ungdom .pdf [Accessed 06 10 2015] Boverket, 2008. Enkät vuxen. [Online] Available at: http://www.boverket.se/contentassets/83d8355da8a64114b1c5ab87cc6105b6/enkat_vuxen.p df [Accessed 06 10 2015] Boverket, 2008. Enkät barn. [Online] Available at: http://www.boverket.se/contentassets/83d8355da8a64114b1c5ab87cc6105b6/enkat_barn.pd f [Accessed 06 10 2015]

Chen, 2009. Effect of thermal storage on actual heat supply in residential building with slab on grade radiant floor heating. [Online] Available at: http://link.springer.com/chapter/10.1007%2F978-3-540-75997-3_507 [Accessed 06 10 2015] Council of European Union, 2015. [Online] Available at: http://ec.europa.eu/clima/policies/package/index_en.htm [Accessed 20 05 2015] Engvall, 1990. Frågeformulär Stockholm. [Online] Available at: http://miljobyggprogramsyd.se/Global/fr%C3%A5geformular%20innemilj%C3%B6%20h %C3%A4lsa%20och%20komfort.pdf [Accessed 06 10 2015] IPCC, 2013. Climate Change 2013 – The Physical Science Basis. [Online] Available at: http://www.ipcc.ch/report/ar5/wg1/ [Accessed 20 05 2015] Onset, 2015. Hobo Temperature and Humidity Data Logger.[Online] Available at: http://www.microdaq.com/occ/ux100/temp-humidity-data-logger.php [Accessed 20 05 2015] SMHI, 2015. Open data. [Online] Available at: http://opendata-catalog.smhi.se/explore/ [Accessed 20 05 2015] Statistikcentralen, 2014. Energiförbrukning inom boende sjönk 2013. [Online] Available at: http://www.stat.fi/til/asen/2013/asen_2013_2014-11-14_tie_001_sv.html [Accessed 20 05 2015] T2, 2002. Handbok för varma, sköna golv. [Online] Available at: http://www.aeservice.nu/pdfer/gv_handbok.pdf [Accessed 20 05 2015]

Appendix A

Hej!

Det ställs mer och mer krav på framtidens bostäder. Man tar fram nya metoder för att värma upp våra bostäder och få ner energianvändningen så mycket som möjligt. Det är viktigt att detta sker på ett sätt där bostadens inomhusklimat inte påverkas negativt.

För att kunna förbättra framtidens bostäder behövs mer information om hur de boende upplever sitt inomhusklimat. Därför skickar nu Lunds Tekniska Högskola ut denna enkät till Er med syftet att undersöka vad ni tycker om er bostads inomhusklimat. Era svar kommer att användas som grund till framtida arbete med utveckling av energieffektivva uppvärmningsmetoder.

Era svar är mycket värdefulla för vårt arbete med att utveckla framtidens bostäder!

Stort tack för hjälpen!

Student Avdelningsföreståndare Joakim Larsson, Ing. Dennis Johansson,TeknDr.

Appendix B

1. Hur många personer bor i bostaden? Räkna med alla vuxna och barn som bor i bostaden minst hälften av tiden.

1 □ Vuxna (18 år och äldre)...... personer

2 □ Barn 13-17 år ...... personer

3 □ Barn 0-12 år ...... personer

2. a) Vilket är husets ungefärliga byggnadsår? År

b) Vilken typ av hus är det?

1 Radhus 2 Kedjehus 3 Parhus 4 Fristående villa 5 Annat c) Hur många våningsplan ovan mark har huset?

1 1 2 1 ½ 3 2 eller fler

d) Hur är det huvudsakligen grundlagt?

1 Betongplatta på mark 2 Torpargrund/krypgrund/plintgrund 3 Källare/souterräng 4 Vet ej

3. Är du nöjd med din bostad som helhet?

1. □ Nöjd 2. □ Ganska nöjd 3. □ Varken/eller 4. □ Ganska missnöjd 5. □ Missnöjd 4. Hur nöjd eller missnöjd är du med bostaden vad gäller..... Nöjd Ganska nöjd Varken/eller Ganska missnöjd Missnöjd

A Storlek? □ □ □ □ □

B Planlösning? □ □ □ □ □

C Dagsljus? □ □ □ □ □

D Trivsel? □ □ □ □ □

E Bostadskostnad? □ □ □ □ □

F Energiförbrukning? □ □ □ □ □ 5. Har du de senaste 3 månaderna känt dig besvärad av någon eller några av följande faktorer i din bostad? Ja ofta (varje vecka) Ja ibland Nej aldrig

A Drag □ □ □

B För hög rumstemperatur □ □ □

C Varierande rumstemperatur □ □ □

D Instängd (”dålig”) luft □ □ □

E Torr luft □ □ □

F Obehaglig lukt □ □ □

6. Hur tycker du att värmekomforten i stort sett är i din bostad? Mycket bra Bra Acceptabel Dålig Mycket dålig

1.□ 2.□ 3.□ 4.□ 5.□ 7. Besväras du av att du i bostaden har... Ja ofta (varje vecka) Ja ibland Nej aldrig

A alltför kallt på vinterhalvåret? □ □ □

B alltför varmt på vinterhalvåret? □ □ □

C alltför kallt på sommarhalvåret? □ □ □

D alltför varmt på sommarhalvåret? □ □ □

E kalla golv? □ □ □

F drag från fönster? □ □ □

G drag från ytterdörr? □ □ □ H varierande rumstemperaturer vi d temperaturväxlingar utomhus? □ □ □

I svårigheter att påverka rumstemperaturen? □ □ □ 8. Vilken typ av uppvärmning finns huvudsakligen på bostadens bottenvåning?

1. □ Vattenburen radiatorvärme 5. □ Golvvärme - vattenburen

2. □ El-radiatorer – äldre typ 6. □ Golvvärme - el

3. □ Elradiatorer – oljefyllda 7. □ Annat

4. □ Luftvärme, dvs varmluft cirkulerar i huset 8. □ Vet ej 9. Vilken typ av uppvärmning finns huvudsakligen på bostadens ovanvåning?

1. □ Vattenburen radiatorvärme 5. □ Golvvärme - vattenburen

2. □ El-radiatorer – äldre typ 6. □ Golvvärme - el

3. □ Elradiatorer – oljefyllda 7. □ Annat

4. □ Luftvärme, dvs varmluft cirkulerar i huset 8. □ Vet ej 8. □ Har ingen ovanvåning

10. Vilken typ av uppvärmning finns i bostadens våtrum?

1. □ Vattenburen radiatorvärme 5. □ Golvvärme - vattenburen

2. □ El-radiatorer – äldre typ 6. □ Golvvärme - el

3. □ Elradiatorer – oljefyllda 7. □ Annat

4. □ Luftvärme, dvs varmluft cirkulerar i huset 8. □ Vet ej 11. Om det finns golvvärme på bostadens bottenplan, vilket golvmaterial ligger ovan det?

1 Linoleum 2 PVC-/plastmatta 3 Heltäckningsmatta 4 Plastlaminat 5 Trä/träparkett 6 Klinker 7 Sten 8 Annat material 9 Har ej värmegolv

12. Om det finns golvvärme på bostadens övreplan, vilket golvmaterial ligger ovan det?

1 Linoleum 2 PVC-/plastmatta 3 Heltäckningsmatta 4 Plastlaminat 5 Trä/träparkett 6 Klinker 7 Sten 8 Annat material 9 Har ej värmegolv

13. Finns fönsterventiler i sovrum/vardagsrum?

1 Ja 2 Nej

14. Hur sker tillförseln av värme till huset?

1 Fjärrvärme/central värmepanna för området 2 Värmepanna i huset 3 Annan 4 Vet ej

15. a) Hur ofta vädras det vanligtvis under uppvärmningssäsongen (d.v.s. september- april)?

1 Dagligen/nästan varje dag 2 Ungefär 1 gång i veckan 3 Någon gång i månaden 4 Vädrar sällan eller aldrig

b) När det vädras, sker det oftast genom att …

1 ...ha vädringsfönster/fönster öppet hela dagen/natten 2 ...ha vädringsfönster/fönster öppet några timmar 3 ...ha korsdrag några minuter

4 Vädrar aldrig 16. a) Har nytt golv lagts in i bostaden under de senaste 12 månaderna?

1 Ja 2 Nej

b) Vilken typ av golvmaterial finns i bostaden? Flera alternativ kan anges.

1 Linoleum 2 PVC-/plastmatta 3 Heltäckningsmatta 4 Plastlaminat 5 Trä/träparkett

6 Klinker 7 Sten

6 Annat

17. Hur varmt är det ungefär i bostaden under .... Vinterhalvåret? Sommarhalvåret?

°C °C

18. Vilken temperatur skulle ni vilja ha i bostaden under... Vinterhalvåret? Sommarhalvåret?

°C °C

19. Om vi har fler frågor angående ert inneklimat hade det varit bra om vi kunde komma i kontakt med er, ber er därför fylla i kontaktuppgifter nedan (om ni absolut inte vill bli kontaktade så bortse från att fylla i).

Namn: ......

Telefonnummer:......

Dept of Architecture and Built Environment: Division of Energy and Building Design Dept of Building and Environmental Technology: Divisions of Building Physics and Building Services