First Author Abstract title Joshua B. Akom Comparison Of Weekdays’ And Weekend’s Indoor Environment In Green Low-income Homes Sofie Andersson Retrofitting from the Inside/Insight Perspective: Adapting to Users’ Needs with the Kitchen as a Starting Point Ann Bosserez Assessments for selecting favourable concepts for building renovation with prefabricated elements Atze Boerstra Energy efficiency of dwellings: a risk factor to comfort and health? An analysis of 8 case study dwellings Anatolijs Borodiņecs Modular prefab integrated HVAC units Wendy Broers Are energy decisions about energy? 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Mørck Experiences from EU MORE-CONNECT Pilot Projects Karel Mulder Future Comfort: Efficiency, control and consumers - Struggles to define the future of residential heating Haico van Nunen Organizing building capacity for NetZero renovation Simona d'Oca Review on the state-of-the-art of deep energy renovation and pre-fab systems in EU-funded projects Mieke Oostra TYPHA Renewable Resource from Rewetted(Peat)land - Exploring a new locally produced, biobased & circular solution for energy efficient buildings Yuting Qi Quality Failures in Energy Saving Renovations of Residential Buildings in Northern China: A Case Study of Huhhot Macarena Rodriguez Effects of Fabric Retrofit Insulation on Temperature Take-Back Fred C. Sanders Refurbishing Construction Material Depots facilitate Dutch Retrofit Housing Georg Schiller Retrofitting building stocks – the perspectives of material flows and circular economy Rizal Sebastian Harmonized Digital Information Platform for Energy - Efficient Building Renovation Marvin Spitsbaard Circular Building Potential within the Energy Transition for Residential Buildings in the Netherlands: a Case Study of the Utrecht-Lunetten District Anne van Stijn Solutions for the coming retrofit challenge: Towards modular, mass customised and circular retrofit products Terttu Vainio Cost Efficient Way to Retrofit Residential Buildings Bas Wouterszoon Jansen Development of a Financial Feasibility Tool for Circular Components: The Case of the Circular Kitchen Mahboubeh Zamani A Review of Research Investigating Indoor Environmental Quality in Sports Facilities Comparison Of Weekdays’ And Weekend’s Indoor Environment In Green Low-income Homes Joshua B. Akom Abdul-Manan Mohamed H. Issa Marten Duhoux ft3 Shokry University of Sadick University of Architecture, Rashwan Manitoba, Canada Deakin University, Manitoba, Canada Landscape & Interior Red River akomj@myumanito Australia mohamed.issa@um Design, Canada College, ba.ca s.sadick@deakin. anitoba.ca [email protected] Canada edu.au mrashwan@ RRC.CA ABSTRACT The goal of this study was to investigate hourly variation of indoor environmental quality (IEQ) in green low-income residential buildings using less sophisticated IEQ equipment. Concentrations were grouped into two categories: (a) weekdays and (b) weekend. Independent t-test was subsequently used to test the differences in these categories. The differences in diurnal cycles of indoor carbon monoxide (CO) and particulate matter (PM) concentrations for weekdays and weekend during the fall season were statistically significant. Similar observation was reported for relative humidity (RH). During the winter period, statistical significance was only observed in temperature. Keywords: Indoor air quality; thermal comfort; green buildings; indoor environmental quality 1. INTRODUCTION The effects of exposure to toxic pollutants, although more pronounced in low-income households (Brown et al., 2015), have received less attention. Poor housing conditions could be detrimental to occupants’ quality of life (Cho et al., 2011). Globally, low-income houses are more likely to be retrofitted to improve performance compared to other classes of housing (Breysse et al., 2011, Breysse et al., 2015, Doll et al., 2016) because of their characteristically poor conditions. Although studies showed significant improvement in energy performance following retrofitting, evidence to support similar claim for IEQ is sparse. One of the main reasons for this inadequate attention is the limited understanding of the indoor environment. Moreover, IAQ problems can hinder energy retrofit strategies e.g. window opening can lead to increased energy consumption (Gupta and Kapsali, 2016). Much is revealed about the indoor environment, including the subtle seasonal and hourly variations, through continuous long-term evaluation compared to snapshot measurements. Another failure of previous IEQ studies is the neglect of the possible different operation conditions of homes, particularly during weekdays and weekends. This study serves as a preliminary investigation attempting to fill this gap and to challenge conventional design assumptions for retrofitting. This study investigates changes in IEQ that may be as a result of seasons and weekly operations. The study will be of utility to designers, policymakers and facility managers in the design, maintenance and operation of green low-income housing on how to leverage on different operation conditions to improve IEQ. 2. METHODS Indoor concentrations were measured in the living rooms of single-family green residential apartments during heating (winter, December 2016-February 2017) and non-heating (fall, September-November 2016) seasons. These homes are located in Manitoba. The Manitoban Province has a temperate climate (i.e. subarctic climate zone), with monthly precipitation averages of 19 mm in January and 48 mm in September. The average monthly maximum and minimum temperatures in September and January are 19 oC and 5 oC and -13 oC and -24 oC, respectively (Climate-Data.org). Often finding inexpensive, easy-to-use, and accurate sensors and equipment is usually a challenge in IEQ evaluation (Heinzerling et al., 2013). With the common commercial sensors, their cost and cost of calibration have been reported as a major hindering factor to the use of objective methods in IEQ studies (Mui et al 2016). In this study, simple foobot air quality equipment was used to monitor CO, CO2, PM, TVOC, Temperature and RH. Compared to existing sensors, these equipment are less-sophisticated and also allow a real-time monitoring of indoor environment remotely. The equipment logged every 5 minutes. Only two apartments were investigated as part of this preliminary study and living room where occupants spent much of their time and thus carried most of their activities was deemed representative of the apartment. The average number of people per home was 6. Data were analysed using parametric independent t-test to test the statistical difference between the two categories. 3. RESULTS AND DISCUSSIONS This section presents the results and discussion of the study. Table 1 summarizes the results. During the fall period, significant difference in CO was reported between weekdays and weekend (p = .00, t = -7.74). The diurnal cycle of indoor CO concentration for the weekend had a characteristic steady trend with a sudden rise in the night (after 7 p.m.), while the diurnal cycle for the weekdays had two characteristic mild peaks, during the morning (8:00–9:00 a.m.) and the evening (4:00–5:00 p.m.). The mild rise in both the morning and evening during the weekday may correspond to a higher traffic flow (perhaps from the nearby highway) during those times of the day as people commute to and from work respectively. Further, the level of concentration on weekend was always higher than weekdays’ concentrations (WD mean = 50.79; WE mean = 87.25). Again, this result was expected since it has been postulated that outdoor sources of CO might be the reasonable influence of the indoor levels (Chaloulakou and Mavroidis, 2002). The apartments have windows opened which would maximize the infiltration of outdoor CO in the apartments. However, no information on air exchange rate which would have been helpful to understand exchanges between indoor and outdoor environment. Notwithstanding, this point is emphasized in the insignificant difference for the winter period where infiltration of outdoor concentration is negated by the closing of windows all the time for thermal comfort. For PM, significant differences between the categories only existed in the fall period (p = .01; t = 2.75). As showed in Table 1, hourly mean concentration