The Nearly Zero-Energy Building Building for the Future Contents

The nearly zero-energy building 3 Regulatory foundation 4 Two ways to achieve the nearly zero-energy building standard 4 energy performance certificate 5 Subsidies 6

Planning 7 Compactness 7 Layout of building zones 8 Orientation – towards the sun 8

Building envelope 9 U-value 9 External walls 9 Windows 10 Thermal bridges 11 Airtightness 11

Heating, water supply and ventilation 12 Heating 12 Hot water 14 Comfort ventilation 15

Active solar energy gains 16 Thermal solar systems 16 Photovoltaic systems 17

Electricity 18

How it works – best practice examples 19 Dieselweg Graz 19 Straw house Ebner 20 Hausmannstätten Elementary School 2 1 Johann Böhm Straße, Kapfenberg 22 Messequartier Graz 23

Glossary 24

Links 25 Europe needs more and more energy, for the most part from non-renewable sources, in order to allow people the opportunity to provide themselves with the comforts they are used to today. This trend cannot continue indefinitely. Therefore, we must implement all measures which reduce energy consumption, increase energy efficiency and promote local, renewable energy sources. In this context, the EU Commission has set up a new framework with its new energy and climate package and brought in several directives which lead the way towards an affordable and sustainable future. Such changes do not always please everyone – as the example of the directive on energy efficiency in buildings shows. Among other things, it stipulates that by the end of this decade, new buildings and buildings undergoing comprehensive renovation may only require very little energy. There is currently a broad discussion on whether such buildings are still affordable – without, however, calling their advantages in terms of energy consumption into question. DStyria has gone a step farther here and has become an internationally recognized pioneer in the construction of passive houses. Beside their minimal energy consumption, the comfort and quality of passive houses speak in their favor. Businesses which have been planning and building passive houses and nearly zero-energy buildings for some time, gaining significant experience thereby, also see the extra cost sometimes claimed as a counter- argument as negligible and offset by the reduction in energy costs. This brochure is meant to provide ideas and support in the planning and use of nearly zero-energy buildings, as well as to make the path to these buildings easier, to the benefit of their users as well as our environment in general. Siegfried Schrittwieser Deputy Governor

“Nearly zero-energy building” and “passive house” are two terms which are popping up ever more frequently in numerous discussions and in the media. But who knows exactly what these terms mean? Yes, clearly they designate houses which require minimal energy for heating (and cooling), but do we need to build houses this way? Does this kind of building offer advantages and what (additional) effort and expense does it entail? Do perfect insulation or innovative heating and ventilation suffice to achieve the nearly zero-energy standard, or are both of these elements required? Do we need renewable energy to get there? This brochure provides details and answers to these and further questions around nearly zero-energy buildings (which differ from passive houses in the slightly less demanding standards, particularly concerning the building envelope). From the regulatory foundation – the EU directive 2010/31/EU on the energy efficiency of buildings stipulates the compliance of all new buildings and all buildings undergoing major renovation with nearly zero energy building standards by 2020 – to aspects of the planning of such buildings, this brochure offers information on the building envelope, heating and ventilation and the possibilities for actively generating energy oneself. In addition, a few detailed examples demonstrate that the respective theory (details of which are found in several standards and the “OIB-Richtlinie 6” [OIB directive 6] and the change needed from today to 2020 is detailed in the “Nationaler Plan” [national plan]) can easily be put into practice. Be it one-family homes or complex buildings, there are already many good examples which also illustrate that these buildings are actually affordable. I would therefore like to thank the motivated staff at the Landesenergieverein (Regional Energy Association) for their work, which is making an important contribution towards understanding nearly zero-energy buildings.

Wolfgang Jilek Regional Energy Officer

1 The “nearly zero-energy building” is known as Niedrigstenergiege-

bäude in Austria and is planned to be introduced as a building stan-

dard for new buildings by the end of 2020. For all public buildings

which could be seen as setting a leadership example, this new buil-

ding standard will be compulsory from the end of 2018.

But what is that really, a nearly zero-energy building? Are even stric-

ter requirements coming, or are we already on the right track? What

do we need to keep in mind when it comes to implementing this new

building standard?

The LandesEnergieVerein Steiermark (Styrian Energy Agency) would

like to answer these and many other questions in this brochure, the-

reby giving orientation on the path toward sustainable and resource-

conserving construction. Photo: LEV Photo:

2 The Nearly Zero-Energy Building

The nearly zero-energy building is a very efficient building with low energy demand. This low energy demand is met mainly through renewable energies generated directly on site or nearby. The nearly zero-energy building standard can be achieved not only in new buildings but also through comprehensive renovation work.

The primary evolution to the current building standard is found in a holistic perspective on and a balanced assessment of the buildings. The analysis focuses not only on the efficiency of the building envelope; rather, an intelligent combination of heating andven- Based on 30-year tilation with renewable energy generation systems such as solar or photovoltaic sys- life cycle costs, a nearly tems, heat pumps, wood or pellet heating is required to obtain an equal balance of all zero-energy building influencing factors. Where less insulation is used, this needs to be compensated for with more offers an optimal cost- efficient heating and ventilation as well as increased gains based on renewable energies. to-benefit ratio.

Building Renewable Energy

compact construction solar panels alignment to the sun photovoltaic excellent thermal insulation ambient heat prevention of thermal bridges biogenic fuels air tightness heat recovery

Besides a healthy living environment, keeping There are a variety of advantages to building a costs as low as possible and the preservation of nearly zero-energy building: our environment are important goals when it comes to constructing or renovating buildings. Comfort When one considers not only the investment §§ pleasant warmth in the winter costs but also takes the running operating costs §§ overheating of the building is prevented into account, the nearly zero-energy building §§ a sufficient supply of fresh air standard achieves all these goals in an optimal §§ brighter rooms due to extensive use of manner. However, low heating and electricity daylight costs during the in-use phase can only be achie- The building’s value increases long-term, and ved through comprehensive planning, diligent its resale value also increases. implementation of the required measures, Low maintenance and operating costs. efficient user behaviour and regular mainte- A positive contribution towards climate pro- nance of the building’s heating and ventilation. tection for generations to come.

3 Regulatory Foundation Two Ways to Achieve the

The requirements In Austria, the requirements for energy-effici- Nearly Zero-Energy Buil- concerning heating ent construction and renovation are defined demand (HD) which in the regional building codes and in the res- ding standard will apply from 2020 pective directives on Wohnbauförderung (re- onward for newly-built sidential building subsidies). The future legal The national plan shows two ways to achieve houses are roughly the measures planned through 2020 are laid out the nearly zero-energy building standard. same as the current in the Nationaler Plan (national plan), a docu- requirements for ment issued by the Österreichisches Institut 2 Heat Demandmax = 34 kWh/m a residential building für Bautechnik (OIB – Austrian Institute of Con- + subsidies in Styria. struction Engineering). Until now, the heating reference equipment of building demand, i.e., the quality of the building en- according to OIB 2007 velope, was the primary focus. The following graph illustrates the evolution of the required or heating demand (HD) values since 2008, including a forecast through 2020, for newly built Heat Demand = 54 kWh/m2a and renovated residential buildings in Styria: max + Maximum heating demand [kWh/m2a] excellent building technology

(fGEE,max = 0,75) 87,5 87,5

75 75 65,5 59,5 This can be achieved either: 56 50 Via a very good insulation standard (HD = max. 45 34 kWh/m2a, dependent on the compactness 36 34 of the building [lc value]) together with a hea- 25 ting and ventilation system meeting the 2007 building code (reference equipment). The 10 10 reference system cannot be modified for this method and no active solar energy generation Building Act Housing Building Act Housing Na�onal klima:ak�v Passive is possible. 2008 Subsidies 2012 Subsidies Plan Standard House 2010 2012 2020 Or:

new building refurbishment Via a good insulation standard (HD = max. 54 kWh/m2a, which is approximately the re- Since the beginning of 2012, the overall ener- quirement of today’s building code) together gy efficiency of a building must be recorded with a very innovative heating and ventilation in its Energieausweis [energy performance system, which can also include a photovoltaic certificate] in addition to its heating demand. system for energy generation. In order to better evaluate overall energy - ef

ficiency, maximum values for the fGEE overall No matter which path you choose, a well-cons- energy efficiency factor, the primary energy tructed building envelope (airtight construction demand (PED) and carbon dioxide emissions and avoidance of thermal bridges) is the pre- (CO2) will be defined on top of the requi- requisite for achieving the nearly zero-energy rements concerning heating demand (HD) building standard. and total final energy demand (TFED). The last two indicators also include transport and generation of the energy sources used.

4 Energy Performance Certificate

The energy performance certificate is a legal document certifying the energy performance of houses and apartments. It evaluates not only the insulation of the components, but rather the entire heating and ventilation system, including heating, solar or comfort ventilation systems.

During the planning-period the energy performance certificate is a valuable tool to compare different em- bodiment variants. For any question contact an independent energy consultant in your neighborhood! A list of authorized energy consultants who issue energy perfor- The first two pages contain a summary of all indicators and data on the building’s overall energy mance certificates efficiency. and undergo ongoing quality assurance can be found on Heating demand (HD) www.net-eb.at The amount of energy which must be emitted by the heating system – such as radiators or underfloor heating – in order to heat the building to a temperature of 20°C. This value primarily depends on the quality of the building envelope, e.g. the thickness of the building’s insulation. The lower this value is, the less energy is required to keep the building warm in the winter!

Primary energy demand (PED) The PED value describes the energy required to provide heating, hot water and electricity for a building. This indicator also takes the effort of energy generation and transport of the energy sources used into account. With the same level of insulation, the primary energy demand of a house heated with oil is therefore higher than that of the same house heated with wood.

Carbon dioxide emissions (CO2)

This indicator includes all CO2 emissions created to meet the overall energy demand of the building. This value also comprises the effort required to transport and generate the energy sources used.

Overall energy efficiency factor (fGEE) This factor indicates how much better or worse the building’s overall energy efficiency x/y – including the heating and ventilation system – is compared to a reference building (Neubaustandard – new building standard – 2007) In general, the same applies here: The lower the value, the more energy-efficient the building!

5 Subsidies (as of June 2014)

new construction subsidies from the Styrian government:www.wohnbau.steiermark.at §§ Family homes: subsidies for building single-family and two-family homes. §§ Multi-story buildings: subsidies for building condominiums and rental apartments.

renovation subsidies from the Styrian government:www.wohnbau.steiermark.at §§ Comprehensive energy renovations: time-constrained renovation work on at least three parts of the building envelope and/or on energy-relevant heating and ventilation systems of an existing residential building. §§ Small renovations: insulation work on individual external building components, individual renovations on the heating and ventilation system. §§ Comprehensive renovations: simultaneous renovations of at least 3 apartments; renovation costs higher than € 30,000 per apartment. At least half of the renovation costs must be used for improvements. §§ Redevelopment in the course of residential building renovations: replacing a large part of an existing building in the same location; the newly-built portion must exceed 50%. §§ Renovation campaign to revive village centers: communities buying existing buildings in village centers and renovating them using funds from building subsidies for residential buildings.

ecological subsidies from the Styrian government: www.technik.steiermark.at §§ Modern wood heating: direct subsidies for modern wood heating systems. §§ Thermal solar systems: direct subsidies for thermal solar systems. §§ Photovoltaic systems: direct subsidies for photovoltaic systems.

federal renovation subsidies: www.umweltfoerderung.at §§ renovation subsidy for private home owners: subsidies for thermal renovations in the private residential building sector for buildings older than 20 years. §§ model renovations: subsidies for comprehensive renovation projects of commercial and public buildings.

federal environmental subsidies: www.umweltfoerderung.at §§ Wood heating: direct subsidies for pellet and wood chip heating systems replacing existing fossil fuel or electric heating systems or minimum 15-year-old wood heating systems. www.publicconsulting.at §§ Photovoltaic systems: subsidies for newly installed photovoltaic systems operated in parallel with the electrical grid. www.pvklimafonds.at Photo: LEV Photo:

6 Planning

A nearly zero-energy house combines very good insulation standards, a high-quality building envelope (no thermal bridges, airtightness) and active energy generation from renewable sources (solar, photovoltaic, ambient heat and biomass).

Diligent planning which coordinates the individual implementation steps is a prerequisite for either building a nearly zero-energy building or for renovating to achieve a nearly zero-energy building standard. Only when the combination of the building components and the heating and ventilation system results in an overall system that actually makes sense can the result be a very efficient house with low energy consumption.

Compactness The advantages of compact construction are: §§ less building and insulation material requi- The geometry of a building decisively influen- red ces its heating demand. Optimal compactness §§ simple connection details and thus a lower Increased com- results in minimal thermal losses. likelihood of construction defects pactness pays off in The smaller the ratio between the surface §§ simpler to complete the airtightness layer several ways: it reduces of the outer envelope (A) and the enclosed §§ fewer thermal bridges the energy required for building volume (V), the more compact the §§ significantly reduced construction costs heating and reduces building. building costs!

There are also possibilities when renovating to improve a building’s compactness. Retrofitting A/V= A/V= insulation on walls or ceilings of unheated areas 0,7-1,0 0,3-0,5 such as basement or attic rooms helps reduce the surface of the insulated building envelope. Closing open loggias with glazing has positive A/V ratio of a free-standing single-family home compared effects and the additional space can be put to to that of a multi-story residential building good use as a winter garden.

To compensate for increased energy losses due to the lower compactness of the building, one can, for instance, increase the insulation level of the building envelope. Effects of a building’s §§ Make your building as compact as possib- compactness on envelope surface and on hea- le – the smaller the surface, the lower the ting demand: thermal losses. §§ Avoid building bays, dormers, juts or offsets as much as possible. §§ Build multi-story buildings instead of bungalows. +10% +20% §§ Insulate walls and ceilings which separate the heated part of the house from unheated rooms such as storage rooms, winter gardens or garages. Increase of envelope surface by 10% (1) or 20% (2) due to differences in compactness

7 Orientation – Towards the Sun

An optimal orientation towards the sun means §§ If possible, when choosing the building maximal heat gains. It is important to be aware lot make sure that the house can be ori- of the available solar energy at each respective ented towards the south and will not be Attention: location both for the passive use, through win- in the shade. future neighboring buil- dows and winter gardens, and the active use, §§ Avoid large window surfaces on the west dings could cast shade through solar collectors and photovoltaic sys- side, because the sun is low in the sky on on solar installations. tems, of solar energy. The angle and path of this side and penetrates deeper into the solar energy on the outer surface of a building building. change both over the course of the day and §§ Expensive external solar screens prevent over the course of the year. overheating but also impair the view. §§ Consider the size and the location of the solar system early: already while planning the building and the roof.

Layout of Building Zones

N E When planning a new building, make sure to place rooms with high heating demand such as the living room or children’s rooms on the south side of the building. Rooms requiring less heat such as the parent’s bedroom or the kitchen can be placed on the north or west side W S of the building. The path of solar energy in summer, spring, fall and winter In order to keep heat distribution losses to a minimum, make sure that the heating or utili- The greatest passive solar gains can be achieved ty room is as centrally located as possible. This through large window surfaces on the south helps reduce pipe lengths and makes it possible side of the building. If the glazing is well cho- to benefit from inside heat losses from boiler sen (degree of energy transmittance G-value and hot water storage. > 50%), the passive gains over the whole year are higher than the losses. Overheating in the summer can be easily avoided with simple construction measures, due to the fact that the sun is high in the sky on the south side in summer.

Where large window surfaces face towards the east or west, choosing an appropriate solar screening strategy should be part of the planning phase. The consequences of an exterior solar screen, such as additional costs as well as

restricted or no view when the solar screen and LEV Photo: glare screen is closed, must be considered. Optimal layout of building zones

8 Building Envelope

A large part of the heat in our interior rooms is lost through the building’s external components It is recommended (windows, walls, floor, roof). The thickness and quality of heat insulation has a decisive influence to coordinate the U- on a building’s energy demand. The indicator of the insulating capacity or quality of a component values of the individual is the U-value. components. The goal should be to obtain §§ The insulation of the building envelope’s balanced insulation U-Value components should run seamlessly over thicknesses around all the individual components. the entire building The U-value, or heat transfer coefficient [W/ §§ Connection details must be carefully envelope. m2K], indicates how much heat is lost through implemented to prevent construction the component. The lower a component’s U- defects. value, the better its heat insulation properties. §§ Materials employed should become gra- In the long run, dually more vapor-permeable from the low U-values lead to inside toward the outside. low heating costs and roof §§ For some types of construction, for increase living comfort 0,12-0,13 instance houses with slanted ceilings, in the winter and the this requires the installation of a vapor- summer. retarder. §§ This type of vapor-retarder must be of wall window good build quality and be properly glued 0,13-0,18 0,8-1,0 in place!

ground plate <0,2 External Walls

Recommended U-values for a nearly zero-energy building Nearly zero-energy houses are not tied to specific building materials. External walls can be The required insulation material thickness for made from bricks (masonry wall construction) external walls, ceilings and floors to achieve a or based on wooden frames (light-weight con- desired U-value of approximately 0.15 W/m2K struction). is around 20-30 cm, depending on the insulating material used. Windows should have a Depending on the insulating material used, the U-value of maximum 1.0 W/m2K. This requires following insulation thicknesses are required: triple low-E glazing with a Ug-value of 0.8 W/ §§ Masonry wall construction: 16-20 cm insu- m2K max. To achieve the highest possible solar lation on vertically perforated brick walls gains, the overall energy transference coeffici- (25-30 cm) ent or G-value should be between 50 and 60%. §§ Framing construction: 30-35 cm insulation between vertical supports and battens A good U-value increases the surface temperature of the respective component, which in The critical elements, however, are the tran- turn increases comfort. sitions between the individual building com- This also prevents surface condensation and ponents and all the connection areas, for in- mold, which is particularly important if there stance when it comes to installing the windows. are large window surfaces. Here you must pay particular attention to a consistent insulation layer without any gaps.

9 Windows

The windows of nearly zero-energy buildings are for the most part coated triple glazing with an overall maximum U-value of 1.0W/m2K. Window surfaces with a low U-value have Which indicators are important?: a considerably higher §§ The U-value of the entire window Uw (w surface temperature, stands for window) is the decisive factor. It which increases com- consists of the mean U-value of the glass

fort. LEV Photo: (Ug), the frame (Uf) and the length-related External wall construction thermal bridge loss coefficient of the glass compound edge (ψ-value). Beware: often Masonry wall construction: only the U-value of the glazing is indicated! §§ Only use coordinated systems and have a §§ The energy transmittance (G-value) of the specialist company carry out the work. glazing indicates the percentage of the solar §§ The insulation plates should be installed energy hitting the window which is trans- using the edge bead spot-gluing method mitted through the glass from the outside and using pegs. toward the inside (passive solar gains). It §§ If the sub-surface is very uneven, for should be at least 50%. instance in case of renovations, we re- §§ Make sure the ψ-values at the spacers bet- commend to apply the glue to the entire ween the glass panes are good (ψ =0.025- surface of the plate. 0.04 W/m2K). §§ Use a vapor-permeable, mineral-based thin plaster for external plaster. When installing the windows, particular attention must be paid to prevent thermal bridges Wooden construction: and leaks which could lead to subsequent cons- §§ Pay careful attention to the proper im- truction defects (mold due to condensation). plementation of the internal airtightness layer (vapor-retarder). The window must be set on the external edge §§ Insulation and battens should be ins- of the wall and insulation should be placed at talled crosswise in two layers, in order to least 3 cm over the frame. mitigate the thermal bridge effects of the Special adhesive tapes and sealants guaran- wooden parts. tee an airtight connection (installation in ac- §§ Use vapor-permeable wind proofing. cordance with RAL guidelines according to ÖNORM B 5320). Photo: LEV Photo: LEV Photo:

Light-weight external wall construction Window installation

10 Thermal Bridges Airtightness Eliminating as many Thermal bridges are weak spots in the building The implementation of a building envelope thermal bridges as envelope. In these areas, more heat is lost via which is as airtight as possible is important possible not only helps a small surface and the surface temperature when it comes to building a nearly zero-energy avoid mold damage but is considerably lower. This can lead to surface building. It prevents excessive cooling of buil- also prevents increased condensation and thereby to mold. Good plan- ding components and uncontrolled heat loss heat loss. ning (implementation details) can reduce ther- through leaks and gaps between components. mal bridges. In this way, it not only minimizes the building’s In a worst case energy consumption, but also prevents moistu- scenario, faulty imple- Typical thermal bridges are: re damage and mold. mentation of thermal §§ Window and door connections (jamb, hea- bridge areas can increase der, blind box, lower connection) a building’s heating de- §§ Connection of external and internal walls to mand by up to 25%. the foundation slab §§ Connection of the basement ceiling to the external wall §§ Connection of the external wall to the roof construction §§ Material changes in a component, e.g. rein- forced concrete beams in the masonry §§ Radiator recesses §§ Protruding balcony slabs §§ Building corners without external insulation in already existing buildings Photo: LEV Photo:

Blower door test

The quality of both planning and implementation determines the airtightness of a building. When the building The building envelope also needs to be as air- envelope is airtight, tight as possible for a comfort ventilation sys- sufficient air exchange tem to work properly. is important. Efficient ventilation, be it manu- al or comfort ventilati- Heat loss through a thermal bridge §§ Test the building’s airtightness via an on, is a must. airtightness test (blower door test). Many of these thermal bridges can be mitiga- §§ Carry out the test as long as the airtight ted very simply by retrofitting insulation.- How layer is still accessible. This enables you ever, since it is not always possible to supervise to rectify possible faults in time. construction work constantly at the building §§ Repeat the test after the building is com- site, timely quality checks, such as testing for pleted. § airtightness and thermal imaging, are a good § The n50-value should be below 1/h. way to avoid construction faults and negative surprises.

11 Heating, Hot Water Supply and Ventilation

Just like there is no single fixed construction type for nearly zero-energy buildings, there is no fixed set of equipment for heating, hot water supply and ventilation. Make sure, however, to coordinate the building with all heating, hot water supply and comfort ventilation components early – during the planning stage – and to keep their energy consumption as low as possible.

Every degree by Heating which the room temperature is lowered saves Energy losses through the heating system can 6% heating energy! account for half of a building’s total final energy demand. That makes it especially important to Pellets are a good pay attention to a few basics for the planning replacement for oil phase. The following heating systems can cover heating, as the demand the low heating demand of a nearly zero-energy for fuel storage space is house in a way that makes sense ecologically. about the same. Biomass Photo: BMLFUW/Rita Newman BMLFUW/Rita Photo:

Pellets, firewood or wood chips are a CO2 neu- Wood chips tral fuel offering high regional value creation. Either central heating systems or individual ovens can be used as heating systems. A pel- §§ Align the performance of the boiler to let-based central heating system, for instance, the low heating demand. A heating load offers automatic heating operation with high calculation will bring clarity. user comfort. §§ Use low system temperatures in the Where a private supply of wood is available, a heating circuit; the temperature should log boiler (wood gasification boiler) is an inex- be below 45°C. pensive alternative. §§ Have a hydraulic balancing carried out. When combined with buffer storage and a so- Proper heating system settings are a -pre lar system, the frequency with which the boiler condition for efficient and problem-free kicks in is reduced, which in turn has effects on operation. the boiler’s service life, on operating effort and §§ Make sure that the heater control is set last but not least on the amount of emissions. correctly. Its task is to adjust the heating performance to the heating demand and thereby to maintain the desired room temperature at a constant level. §§ Have the boiler cleaned and checked regularly by a specialist. Bad maintenance leads to soiling, which increases energy consumption. Photo: BMLFUW Photo:

Log storage

12 Heat Pump District and Local Heating Heat pumps requi- The heat pump takes ambient heat from earth, District and local heating are both very user-fri- re little space and take water or air and uses electricity to increase it to endly and comfortable. They save a lot of space no fuel storage space. the temperature level required to heat a buil- since only a small transfer station connecting Maintenance is simple, ding. the district heating grid to the building’s heat and no CO2 or fine dust distribution system has to be installed in the emissions are produced Depending on the heat source, more or less building itself. This eliminates dirt and noise in locally. Attention: only if electricity is required. An air heat pump, for in- the house and also reduces installation costs. all efficiency require- stance, is less efficient than a geothermal heat Availability and connection possibilities must ments are fulfilled can pump, since the air temperature is lowest in be checked with the operator of the heating one really expect low the winter when the building needs heating. plant in advance. Ecologically speaking, a hea- heating costs! The prerequisite for the efficient operation of ting plant using biomass or waste heat with co- a heat pump is very good heat insulation and generation of heat and power makes the most thus low heating demand. sense.

§§ Always use a low-temperature heat supply system (e.g. underfloor or wall heating) in combination with a heat pump. §§ Preferably use earth or water as heat sources, as they provide constant temperatures all year round. In principle, it is §§ If you use earth as a heat source, check also possible to use the whether the soil is suitable (humid, heat pump to supply heavy). hot water. However, as

§§ Make sure the seasonal performance Newman BMLFUW/Rita Foto: the temperature requi- factor is high. It should be at least 4 (air Local heating biomass boiler red for this is conside- heat pump 3.5), 1 part electricity results rably higher than the in 4 parts heat. low supply temperature §§ Check the seasonal performance factor for the heating, the by installing a heat meter. §§ Have the contract for heating supply pump has to work a lot checked by an independent consultancy harder. This not only agency in advance. reduces the heating pump’s efficiency by 20 to 30%, but also requires more electricity. Combining the heat pump with a solar system is advisable.

Schematic of a heat pump with geothermal heat collectors (1), depth drilling (2), usage of well water (3) and air (4) as heat sources

13 Heat Supply and Distribution Hot Water

Based on the The heat supply system transfers heat into Water heating should always be coordinated mindset “It’s better to the rooms. Modern heating systems have low with the existing heating systems. From an be too warm than too supply temperatures and large heat emitting ecological point of view, it makes the most cold,” the parameters surfaces (underfloor heating, wall heating, and sense to use a thermal solar system to heat of heating systems are low-temperature radiators). Low surface tem- water. If this is not possible, the boiler can be often set incorrectly. peratures of heat emitting surfaces save energy used to heat water during the heating season. Uninsulated heating and provide a high level of comfort. In the summer however it is not efficient to pipes in the basement use the boiler solely to heat water. In this case, and overlarge heating an electric immersion heater integrated into pumps waste even the hot water storage or a heat pump can be more valuable energy. used to heat water. This can be expensive! The average water consumption of an average Austrian household is approximately 135 l per person per day. As is the case for electricity, it A thermal solar makes sense to monitor water consumption system can heat and and to keep it as low as possible. maintain at the ready up to two-thirds of the

hot water demand over LEV Photo: the entire year. Underfloor heating pipes

Since after a well-insulated building envelope §§ Make sure the storage insulation is at the heat supply system is a main factor for the least 10 cm thick. level of comfort inside rooms, a specialist com- §§ Insulate the pipes in order to avoid unne- pany should plan the layout and implement cessary losses. the accurate installation. Hydraulic balancing §§ Position the storage as close as possible also requires expert know-how and measuring to the tapping points. This avoids energy- tools. intensive circulation.

§§ Choose a heating system with low system temperatures (30°-55°C). §§ Insist on careful dimensioning of the heat emitting surface. The required heating performance should be achieved but not exceeded. §§ Have an expert carry out the hydraulic balancing of your heating system. §§ Make sure the lines are as short as possible. §§ Insulate distribution lines and pumps.

Schematic of a solar system

14 Comfort Ventilation

Sufficient fresh air is important for a high level The fresh air from outside is taken in centrally, Windows can still of household comfort. A comfort ventilation filtered and guided past the heat exchanger. be opened when a ven- system provides good room air quality all year The waste air from the inside rooms is also gui- tilation system is used round and heat recovery saves additional valu- ded past the heat exchanger and thus heats the – most of the time, able heating energy. Pollutants and humidity cold air from outside. The preheated air is then however, there is no are removed, which reduces the risk of mold. distributed in the building via pipes. need if the air quality The basic prerequisite for the efficient operati- remains good. on of a ventilation system is an airtight building envelope. Depending on the heat exchanger type, it can extract more or less heat from the outgoing air. This airtightness should be checked using the You should use the heat recovery efficiency as a blower door test. When retrofitting a ventilati- comparison parameter. It provides information on system, one needs to check in advance whe- on the efficiency of the entire device (not only A comfort venti- ther there is enough space available and whe- that of the heat exchanger) and should always lation system can save ther all preconditions for a central ventilation be higher than 70%. approximately 2,000 – system are met. Decentralized, room-specific 3,000 kWh per year in devices can be used as an alternative. an average household. 300 kWh of electricity are required for its §§ Make sure that heat recovery is high and operation. electricity consumption is low. §§ When planning the pipe system, make sure the pipes are short and the layout is simple and accessible. Avoid acute angles in the pipe system. §§ Adapt the air supply intake (air quanti- ties) to the actual demand depending on the number of persons and their physical presence. §§ Change the filter at least once a year. This prevents soiling. Photo: LEV Photo:

Comfort ventilation system

A comfort ventilation system with heat recovery basically consists of a central ventilation unit with an integrated heat- ex changer and a pipe system for air distribution. Photo: LEV Photo:

Ventilation outlet

15 Active Solar Energy Gains

Solar energy is Energy gains through thermal solar or photovoltaic systems improve a building’s total final energy always available at no demand. This increases overall efficiency and the energy gains help meet requirements. charge and thus offers price stability over many years. Photovol- taic power generation Thermal Solar Systems and thermal solar systems are options Heating water using the power of the sun has Evacuated collectors are available as flat-plate for using solar energy been state of the art for some time. Thermal or tube collectors. They are particularly effici- directly. solar systems reliably provide free of charge ent when generating very hot water at low out- energy and are without competition in particu- side temperatures. lar during times of rising energy prices. Depen- ding on the system type, thermal solar systems Usually the solar system is integrated into the are used for water heating or, additionally, for roof. An alternative is a separate installation Heating water for solar-assisted heating. Approximately 70% of in the garden or an integration into the faça- a 4-person household the hot water demand of a one-family home de. The optimal installation angle is between requires 8 m2 collector can be covered by a solar system. 20 and 70 degrees. The collectors should face surface and a 400 l south. Hot water solar systems should not ex- solar storage. ceed an offset of 45 degrees toward the east or west. Solar-assisted heating requires at least 15-20 m2 collector surface and a 1,000-1,500 l buffer storage. Photo: LEV Photo:

Thermal solar system on the roof

At the same time, the service life of the hea- Photo:BMLFUW ting system is increased due to the reduced Thermal solar systems frequency of operation. Where a solar system is used in combination with a heat pump, the ground has enough time to recover during the §§ Make sure your solar system faces as summer. directly south as possible. If the solar system is integrated into the hea- §§ Insulate the hot water storage (at least 12 ting system, it provides additional heat for the cm) and the pipes. house during transitional periods and supports §§ Make sure to adjust the dimensions of the heating system in the winter. In this case, your system to the area of application. the solar system is combined with the heating §§ Install a heat meter in larger systems to system via a buffer storage. check the yield. §§ Have a specialist company carry out The core of a thermal solar system is the coll- maintenance on your system every 2-3 ector. There are flat-plate collectors which are years. preferred for domestic water and room heating.

16 Photovoltaic Systems

A photovoltaic system directly transforms sun- §§ Obtain a performance guarantee: minimum With an optimal light into electricity. 80% of the rated capacity for 25 years. inclination of 30° and The electricity is created in the solar cells en- when the panels are tirely without producing noise or emissions. The generated direct current is converted into oriented towards the Photovoltaic systems can be installed on roofs, alternating current via an inverter and can south, in our latitudes façades and other suitable surfaces and are ne- then be used predominantly for direct hou- an average of 1,000 arly maintenance-free. sehold consumption. Any excess can be fed kWh of electricity per into the power grid or stored in special solar year is generated for batteries. each 1 kWp of installed photovoltaic perfor- The system efficiency factor indicates what mance. Depending on percentage of the generated power is really the type of module, 1 available for use. With modern systems this kWp is the equivalent factor is between 70% and 90%. of a surface of approximately 7-10 m2. Phto: LEV Phto:

Photovoltaic system

The cells are made mostly from silicon. Most of the time polycrystalline cells with an uneven surface are used. They are inexpensive to manufacture and have a cell efficiency of up to 15%.

PV modules are offered with and without frames. In particular if installed on flat roofs, framed modules don’t clean themselves as well

of snow, dirt etc. However, the frame protects LEV Photo: the sensitive glass edges during assembly. The- Transparent PV panels re are also semitransparent modules, i.e. modules which allow light to pass through them, for special applications. §§ Make sure to plan carefully. The size of the installation, its location on the building and possible locations for inverters Only buy solar modules which fulfill certain and lines should be clarified beforehand. quality criteria and pay attention to the follo- §§ Avoid shading. Just a little shade can wing points: reduce performance significantly. §§ Make sure to plan carefully. The size of the §§ Allow for sufficient underside ventilation installation, its location on the building and of the modules (at least 10 cm). Efficiency possible locations for inverters and lines decreases with increasing temperature. should be clarified beforehand. §§ Clarify the connection conditions with the §§ The power tolerance should be at least +/- responsible grid operator. 5% or less since the weakest module defines the power for all modules when the modules are connected in series.

17 Electricity

There are several possibilities to keep the power consumption and thus electricity bills in your building low. The majority of the power consumed in households is used for hot water and heating, which is why the energy required to drive pumps and fans must be kept as low as possible. The area of household electricity, however, also offers great savings potential.

Average power consumption per household in 2012:

22% - hea�ng and air condi�on: 12% - cooling and freezing equipment hea�ng, circula�on pump, fan, air humidiﬁers and dehumidiﬁers, air condi�oner, auxiliary hea�ng 15% - kitchen equipment: stove, oven, dishwasher, other kitchen devices

4.417 6% - washing machine, 17% - hot water prepara�on kWh pro direr Jahr

9% - lightening 15% - oﬃce and entertainment devices, 4% - standby communica�on: PC, laptop, TV, fax, cell phone etc.

Data: Statistik Austria Using less electricity pays off because How much you can save in energy and costs in If you don’t use energy-intensive devices and electricity is the most your household depends primarily on your be- make conscious use of daylight in order to mi- expensive type of haviour. By changing your behaviour or buying nimize artificial lighting, there will be less waste energy used in the hou- more efficient appliances, meaning changing heat inside the building. As a result, you won’t sehold. Implementing the technical equipment you are using, you can need air conditioning to feel comfortable in simple tips and buying achieve your maximum overall savings poten- your home in the summer! efficient appliances tial. can help you prevent Tips for saving electricity unnecessary waste of electricity, thereby §§ Use multipoint connectors that you can saving up to 30%, or switch on and off. The on/off switch dis- around € 260.00, off connects all plugged-in devices from the your electricity costs! grid when you switch it off, which avoids standby consumption. §§ If there are longer interruptions of usage

Photo: LEV Photo: (also overnight!), switch off all inactive Ampere meter devices (computer, modem, radio etc.) completely or disconnect them from the Only buy a new appliance if you absolutely grid via the multipoint connector. need it or if repair of the old appliance is either §§ Laundry dryers are true “energy sappers”! no longer possible or makes no sense from an New heat pump dryers also consume energy saving perspective. Make a conscious energy. It is better to let your laundry dry decision not to use devices which run all the on a clothesline or a clotheshorse. time or which have a high standby consumption!

18 This is how it works – best practice examples Facts Building envelope Dieselweg Graz External walls: U = 0.09 - 0.18 W/m²K Roof: U = 0.09 W/m²K Windows: U = 0.83 - 0.95 W/m²K Floors: U = 0.13 - 0.19 W/m²K

Heating, hot water supply and ventilation §§612m² of solar collectors §§Non-pressurized buffer storage §§Decentralized room ventilation units with heat recovery §§Groundwater-fed heat pump system

Indicators

Photo: GIWOG Photo: Heating demand HD before renovation: The building “Soziale Wohnsiedlung in Graz-Liebenau, am Dieselweg gelegen“ (Social housing 142 - 225 kWh/m²a complex in Graz-Liebenau on Dieselweg) is an example for the implementation of high-quality After renovation: renovation technologies and the use of renewable energy sources in social housing residential 9.6 - 13.6 kWh/m²a buildings. The GIWOG, a social building project organizer, used GAP façade panels to renovate the external Standards declaration walls. The honeycomb structure made from recycled cellulose, protected by rear-ventilated gla- and awards zing, increases the surface temperature of the walls nearly to room temperature. This increases §§Energy Globe Styria comfort and reduces operating costs. In the summer, the solar honeycomb structure creates its Award 2009 own shade due to the fact that the sun is so high in the sky. Shading systems are not required. §§Nominated for the The energy demand for hot water and heating is met exclusively via the façade. Energy Globe World Award 2010 www.giwog.at/projekte/referenz/passivhaussanierung-graz-dieselweg.html §§Nominated for the Austrian Climate Pro- tection Award 2009 §§1st place in the Buil- ding Sector Initiative 2009 §§Exemplary Residential Building Construction 2010 §§Passive house Photos: GIWOG 19 Straw house Ebner

Facts 160 m² usable floor space (120 m2 living space, 40 m2 doctor’s office)

Building envelope External walls: U = 0.07 W/m²K Roof: U = 0.07 W/m²K Windows: U = 0.75 W/m²K Floors: U = 0.11 W/m²K

Heating, hot water supply and ventilation §§8.5m² solar collectors §§500 l buffer storage §§6 kW pellet-fired

heater LEV Photo: §§Central living space ventilation system The house owned by the Ebner family, built using partially-load-bearing straw bale construction, is with heat recovery a combination of a family home and a built-in office.

Indicators In order to be able to implement eco-friendly construction at the lowest possible cost, the decision Heating demand: was made to use straw bales as construction material.

HD = 9.0 kWh/m²a The 5 cm thick loam plaster and the CO2 level controlled ventilation system provide a healthy room Total final energy climate and a good moisture balance. demand: Since the building faces the SSW, solar radiation can be utilized almost optimally. The generous TFED = 25.0 kWh/m²a overhang of the attached barrel roof provides sufficient shade in the summer. Primary energy de- The solar collector integrated into the balcony does double-duty as balcony balustrade and pro- mand: vides an optimal amount of solar heat during transitional periods and in the winter thanks to its PED = 46.0 kWh/m²a 75° inclination.

CO2 emissions: 5.4 kg/m²a

Standards declaration and awards §§klima:aktiv silver award (751 points) §§Passive house

Photos:LEV

20 Hausmannstätten Elementary School

Facts Usable floor space: 1,650 m² 12 classes 220 students 25 teachers Glass surfaces: 564 m² Building envelope External walls: U = 0.22 W/m²K Roof: U = 0.17 W/m²K Windows: U = 1.0 W/m²K Floors: U = 0.2 W/m²K

Heating, hot water supply and ventilation §§Daylight-controlled lighting and shade

Photo: Paul Ott Paul Photo: §§Controlled ventilation with precooling/pre- The new Hausmannstätten Elementary School, planned by the .tmp architects Uli Tischler and heating via geother- Martin Mechs, is a building which weaves together landscape and architecture. The three-story, mal wells flat-roofed building has a pre-greyed wooden façade into which differently-colored porches are cut §§Underfloor heating on all sides and is nestled against the gentle slope next to the brook. §§District heating Indicators Community and staff rooms are on the ground floor, classrooms, loggias and terraces can be found Heating demand: on the upper floors, which makes it possible to hold classes outside anytime. Light penetrates HD = 24.2 kWh/m²a deeply into the school building and the large windows in the classrooms offer sweeping views. Total final energy The building offers generous spaces to move around in with niches and tilted angles where multi- demand: class courses can be held, the students can play and which are also used when the weather is bad TFED = 54.4 kWh/m²a outside. Primary energy demand: www.t-m-p.org/preview/ PED = 91.9 kWh/m²a

CO2 emissions: 11.4 kg/m²a

Awards §§GerambRose 2012 §§Architecture Award of the Styrian Govern- ment 2013 §§Better Learning Space Photos 1-3: Paul Ott, photo 4: LEV Award 2013

21 Johann Böhm Straße, Kapfenberg

Facts 2,240 m² usable floor space 32 apartments

Building envelope External walls: U = 0.12 W/m²K Roof: U = 0,10 W/m²K Windows: U = 0,85 W/m²K Floors: U = 0,30 W/m²K

Heating, hot water supply and ventilation §§144 m² solar collectors §§630 m² photovoltaic §§7,500 l buffer storage

§§District heating SG Ennstal Photo: §§Central living space ventilation system In the course of the renovation of this residential building constructed in the 50s by the ENW and with heat recovery the SG Ennstal (social building project organizers) in Kapfenberg, a modern building which, due to extensive photovoltaic installations, now has the energy balance of a plus energy house was Indicators created out of a poor quality, in terms of energy consumption, building fabric. PV collectors and Heating demand: thermal solar collectors generate more energy on the building than is required for its operation. HD = 14.0 kWh/m²a The renovated building benefits from prefabricated timber construction modules, into which he- Total final energy ating, hot water supply and ventilation are integrated and which are attached to the massive buil- demand: ding. This turns a residential building from the 50s into a thermally optimized building with high- TFED = 43.0 kWh/m²a quality technical equipment. Primary energy de- At the same time, the residents benefit from numerous added-value aspects, such as increased mand: comfort, more light inside and fully renovated and barrier-free apartments. PED = 80.0 kWh/m²a

CO2 emissions: www.wohnbaugruppe.at, www.nussmueller.at 20 kg/m²a

Standards declaration and awards §§ klima:aktiv gold award (943 points) §§Austrian Sustainable Building Council (867 points) §§Plus energy house Photos: SG Ennstal

22 Messequartier Graz Facts Building envelope External walls: U = 0.18 - 0.25 W/m²K Roof: U = 0.08 - 0.16 W/m²K Windows: 3-Scheiben-Wärme- schutzverglasung Floors: U = 0.16 - 0.24 W/m²K Heating, hot water supply and ventilation §§706 m² solar collectors §§3 x 25,000 l buffer storage §§Central living space ventilation system with heat recovery §§District heating Indicators Heating demand: HD = 9.2 kWh/m²a

Photo: LEV Photo: Total final energy demand: In the course of an urban development plan the city of Graz held an architecture competition in TFED = 27.14 kWh/m²a 2006, the goal of which was to draw up a development plan for the former trade show site. The Primary energy de- Markus Pernthaler Architects Office won the competition. mand: PED = 66.0 kWh/m²a

In 2007 the social building project organizers ENW and SG Ennstal bought part of the site in order CO2 emissions: to construct a multi-functional and eco-friendly residential project. Inaugurated in 2012, the “Mes- 13.4 kg/m²a sequartier Graz (Graz Trade Show Quarter)” is currently the largest passive house project in Styria Standards declaration (usable living space: 16,947 m2, service space: 3,627 m2) with 149 apartments, 21 apartments and awards for senior citizens, a students’ residence with a capacity of 97, 404 underground parking garage §§Federal Award for spaces and 547 bike parking spaces, a kindergarten with a daycare center and a swimming pool Architecture and Sus- on the roof. tainability 2012 §§Special Award “Ex- www.markus-pernthaler.at, www.wohnbaugruppe.at emplary Residential Building Construction 2012” from the Styri- an government §§eco-pass evaluation: apartments rated 4 “Excellent” and 4 “Very Good” for a total of eight criteria §§klima:aktiv bronze Photos: LEV award (738 points) §§Passive house 23 Glossary

Blower door test The blower door test can be used to measure the airtightness of a building. A fan creates a differential pressure of 50 pascals. During the test, the volume of incoming and outgoing air is measured. The resulting air volume flow and the building’s air volume are used to

calculate the air change rate n50 (at 50 pascals).

Energy from renewable energy sources This is energy from renewable, non-fossil energy sources, i.e. wind, sun, aerothermal, geothermal and hydrothermal energy, ocean energy, water power, biomass as well as landfill gas, sewage gas and biogas.

Overall energy efficiency of a building This is the calculated or measured energy quantity required to cover the energy demand for standard operation of the building (among others heating, cooling, ventilation, water heating and lighting).

Heat energy demand/total final energy demand The energy quantity required to cover the heating demand, water heating demand and all losses from heating and water heating.

Heating demand Heating demand is the quantity of energy which must be emitted by the heating system (radiators or heating devices) into the rooms which need heating in order to achieve a defined temperature in these rooms (effective energy). The heating energy for heating water and losses from heating and hot water pipes are not included.

Hydraulic balancing For a heating system to work perfectly, the radiator must contain exactly the right quantity of hot water. This is not something that just happens. It requires exact hydraulic balancing which is also referred to as “adjustment” after the heating system is assembled and has been filled with water. Faulty hydraulic balancing can lead to malfunction as well as increased fuel and pump energy demand.

Nearly zero-energy building This is a building with very high overall energy efficiency. A subs- tantial part of the almost zero or very low energy demand should be covered by energy which is generated mostly on site or close by from renewable sources.

Passive house This is a building which does not require an active heating or air-conditioning system. It uses the energy sources inherent in the building such as solar radiation, body heat of the people living in the building and waste heat from electrical appliances.

Plus energy house This is a house with a positive annual energy balance. It collects more energy than it requires from outside sources. There is no official definition for this term, no defined energy balance limit and no clear definition on whether only energy generated on site can be taken into account.

Primary energy demand In addition to the total final energy demand, the primary energy demand includes the energy quantity required due to upstream process chains outside the system limit of the building for the production, transformation and distribution of the energy source.

24 Links www.gdi.at Platform for eco-friendly construction material of the Insulation Industry Interest Group www.raumluft.org Platform on ambient air www.komfortlüftung.at Comfort Ventilation Association www.guetesiegel-erdwaerme.at Geothermal Energy Quality Society, information on the heat pump www.solarwaerme.at Information on solar systems www.pvaustria.at Information on photovoltaic systems www.topprodukte.at Energy-efficient products and devices for lighting, offices, households, heating/hot water/air conditioning, mobility, communication and entertainment www.haus-der-baubiologie.at Center for Healthy Building and Living www.igpassivhaus.at Platform for innovative buildings www.sonnenhaus.co.at Initiative for houses which use solar energy to cover most of their heating demand www.net-eb.at Styrian Energy Consultancy Network www.ich-tus.at Energy saving and climate protection initiative of the Styrian government www.klimaaktiv.at Austrian Climate Protection Initiative by the Federal Ministry of Agriculture, Forestry, Environment and Water Management Legals : The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the EACI nor the European Commission is responsible for any use that may be made of the information contained therein.

Responsible for the content: LandesEnergieVerein Steiermark project team Concept: DI Ulla Baur-Gschier, DI Heidrun Stückler, Ingrid Mayrhofer Typesetting/layout/graphics: DI Heide Rothwangl-Heber Photos and figures (if not indicated otherwise): LEV Title photo: Tannhausen Community Center by Kaltenegger & Partner Architekten ZT GmbH, Photo: Harald Eisenberger Printing: Onlineprinters GmbH We assume no responsibility for printing and typesetting errors Version: 06/2014, print run: 50