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There is growing evidence that terraced houses—thermally lightweight, well insulated, naturally ventilated with three exposed wall surfaces—are at risk of overheating, especially in south-eastern England. The aim of this study is to evaluate the building performance and develop a reliable building simulation, which will be employed in the second phase of the study: developing affordable and feasible passive design strategies to support the energy-efficient building systems of the construction industry. This paper reports on the results from the first phase of the study where a quantitative methodology, including indoor and outdoor environmental monitoring, in-situ measurements and building simulation modelling, was adopted. The performance of a case study was modelled and simulated via employing Integrated Environmental Solutions (IES) software suite. The results from the base-case were analysed according to the adaptive thermal comfort of Chartered Institution of Building Services Engineers (CIBSE) Technical Memorandum 52 guidelines: The Limits of Thermal Comfort—Avoiding Overheating in European Buildings. The spaces studied within the case study house were observed to exceed the acceptable limits of thermal comfort; particularly, the large bedroom within this zone exceeded the upper limit for overheating up to 11 h daily. Furthermore, the results from the monitoring study indicate a high risk of summertime overheating across all the case study settings, especially during short-term peaks in outdoor temperatures. The main reasons for the problematic thermal performance were identified as well-insulated and fully air-tight building fabric, the lack of sufficient ventilation through the living spaces and excessive heat gains through the composite cladding material.

This study evaluated the performance of three different quilts (white duck down quilt, white goose down quilt and cotton quilt) based on sleep quality and thermal comfort of young people in non-heating bedroom in winter. Thermal comfort and sleep quality were subjectively evaluated before and after sleep. Electroencephalograms (EEG), skin temperatures and bed climate were measured throughout the all-night sleep. Both subjective and physiological results showed that quilt materials had a significant effect on sleep quality and thermal comfort. The goose down quilt was evaluated the most comfortable in overall sleep comfort and sleep thermal sensation. The duration of slow wave sleep as calculated by EEG signal was longer, the skin temperatures and bed climate were higher when the goose down quilt was used. The results also show that there are gender differences in skin temperatures. Compared with males, the mean skin temperature (MST) of females was higher, while their foot temperature was significantly lower, which suggest that for females more attention should be paid to maintain warmth of extremity during sleep in winter. Our results suggest that sleep quality and thermal comfort is the most desirable when using goose down quilt and undesirable when using cotton quilt. Duvet could guarantee a comfortable bed climate in non-heating bedroom in winter of East China. Results also showed that lighter quilts would have a higher degree of satisfactions, indicating that young people in East China may have a preference for light quilt.

The Europe Union needs to reduce its carbon emissions. To achieve the proposed 55% emission reduction target by 2030 it has embarked on a Renovation Wave which aims for more, and deeper, building renovation. Considering this ambition and the scale of the challenge, there remains a surprising paucity of documented post occupancy evaluation studies of deep retrofit projects, particularly those related to the new nZEB standards and of group housing schemes. This paper reports on the post-retrofit performance of a community of 12 single story, one bedroom social houses located in the southeast of Ireland, occupied by retired and elderly tenants. The deep retrofit works included the upgrade of the building fabric, ventilation and heating, all with a view to transforming the living standards of the occupants. They in turn responded, when surveyed, with near unanimous satisfaction. The upgrade and the addition of onsite microgeneration ensured these houses were transformed from lowly F and G national building energy ratings (BER) to A rated homes as calculated by the national energy rating software, DEAP. However, a performance gap is reported between the expected A performance ( This post occupancy evaluation, post retrofit, provides evidence therefore of high occupant satisfaction, but a satisfaction based on significant energy ‘underperformance’. This case study provides evidence and insights that can help guide future retrofit practices as Ireland progresses towards the transformation of its building stock to near Zero Energy Buildings (nZEB). It also opens up serious questions around the aims and expectations of our national nZEB standard and generates some key insights into the energy consumption of nZEB dwellings and the assessment methods necessary to measure them accurately .

Domestic zonal heating controls enable hydronic systems to heat rooms to different temperatures at different times. The first credible evidence known to the authors, of the in-use energy savings of such controls, is reported. The results and research methods are globally relevant. The energy demands and room temperatures in 68, gas-heated, owner-occupied, semi-detached homes, in the English Midlands were monitored for a year before zonal controls were fitted in 37 of the homes prior to the second year of monitoring. The other homes retained the existing heating controls and so provided a matched (control) group. Surveys and questionnaires characterised the dwellings, heating systems and households. In two thirds of the homes with zonal controls the annual gas demand decreased, in one third it increased. Overall, the mean gas demand decreased by 3.5% relative to the homes that retained their existing controls. Savings were achieved primarily by reducing bedroom temperatures, especially in the evenings. Wireless, digital zonal controls are unlikely to provide an acceptable payback through reductions in energy bills at today’s prices, but they offer households the flexibility to react to time-of-use energy pricing. A matched (control) group is essential for the reliable calculation of energy demand changes arising from interventions in occupied homes.

Window opening behavior is a common and effective way for occupants to improve indoor thermal comfort and air quality. There are many studies on the window opening behavior in residential buildings, but research on infant families is still lacking. This paper examines the window opening behavior of four infant families in Beijing and Tianjin that are located in a cold region of China during the transition season. The Kendall Tau coefficient is used to measure the correlation between behavior and environmental factors for the first time. Two types of windows opening behavior were found: i) related to environmental factors and ii) independent of environmental factors. The study reveals that the window opening probability in the living room of infant families is 70.6%, and in the bedroom is 57.2%, which is obviously higher than the existing research on ordinary residents (24.3 ∼ 43.2%). The window opening probability of infant families shows a more obvious downward trend with increasing outdoor PM2.5 concentration compared to ordinary families. Non-environmental factors, such as time of day and age of infant, also affect behavior. Based on the proposed concept of indoor CO2 driving strength (DSCO2_In), it was concluded that the variation of the indoor CO2 concentration is the result of the window opening behavior rather than a driving factor. The logistic regression model shows that outdoor temperature and PM2.5 concentration are the most important factors. This study can help us gain a thorough understanding of the window opening behavior in infant families and it can also provide data and theoretical support for of the simulation of energy consumption in infant families.

Looking back to the glorious years of Brazilian modernism between 1930 and 1964, the country´s architectural heritage reveals an environmental design approach still relevant to buildings of today. In this context, the COPAN building (1966), located in Sao Paulo (latitude 23°S), is one of the most iconic buildings of its time with 1.160 residential units encompassing various types of studio flats (called in Portuguese “kitnets”) as well as one, two and three bedroom apartments distributed across six blocks of independent vertical circulation accesses. This naturally ventilated tall building is recognized by its massive concrete curvilinear structure of 140 m high, shaded towards the north and northwest orientations by horizontal concrete brise-soleis and opened with a single glazed curtain wall on the south and southeast orientations. The thermal performance of the Copan building was investigated by means of fieldwork and analytical procedures. The fieldwork included measurements in loco of environmental variables in four residential units, during warm and cooler periods of the year (2016) and interviews with a sample of 100 occupants, this was followed by thermal dynamic computer simulations performed with the Thermal Analysis Simulation Software (TAS). The adaptive comfort model defined in ASHRAE 55-2013 was adopted as the performance criteria for analytical studies. One of the main conclusions of these technical studies was about the combined effect of thermal inertia, external shading and controlled natural ventilation resulting in steady thermal conditions, with air temperatures oscillating between 24 °C and 26 °C when external temperatures reach as high as 32 °C in a typical warm afternoon.

An intensive study on the heating temperature aimed to create a satisfying indoor condition that should meet the residents’ thermal requirements in accordance to their daily behavior pattern. Unlike urban residents who stay indoors for a long time, rural residents constantly live in a dynamic environment: they often leave their residences and get busy with numerous labor activities. Therefore, the thermal sensation questionnaire survey performed in a steady environment is not suitable for them. To study the rural heating temperature in a dynamic environment, a three-years field investigation was performed in South Liaoning province. During the investigation, a continuous tracking method was adopted to record the residents’ behavior; objective environmental parameters test and subjective thermal sensation surveys were rigorously recorded. The results indicate that the residents behavior pattern exerts an influence on the heating temperature by influencing the residents’ clothing insulation. Heating temperature in auxiliary rooms can be directly determined by the residents’ thermal sensation, with the reasonable value of 11 °C. The influence of residents’ behavior on clothing should be considered when determining heating temperature in the master bedroom, the reported value of which is 13 °C. The heating temperature obtained by the thermal sensation fuzzy comprehensive evaluation model in paper reflects the rural residents’ real-life requirements on thermal environment, and it provides a reference for designing rural residences.

Many elderly New Zealanders live in houses larger than they need and some find it difficult to maintain them. Some struggle on while others prefer to move to retirement villages or similar options. This study takes a typical three bedroom house in New Zealand and shows it is possible to convert this into small units for the independent elderly to enable ageing in place. The aim was to see the resource use impacts of each housing option. Two schemes are shown, one with separate units and a shared entrance and one with separate en-suite bedsits with shared living spaces. The conversions meet the New Zealand Lifemark standards for such housing and provide the type of accommodation found in retirement village units. Seven scenarios were created for households in both the original and converted house. A life-cycle energy assessment of each scenario of the house before and after conversion, including its operating energy and the energy embodied in the building and furniture, appliances, and tools shows that occupancy and design are key factors in whether resources can be saved using this approach. Over 50 years the conversion with 4 occupants showed a 27% saving in life-cycle energy (per person). However, 2 people living in the original house used less energy per person over 50 years than either 2 or 3 people living in the same house converted into two separate units. This is because of the duplication of appliances and furniture and more use of hot water in the two bathrooms. The resources going into converting the house were minimal.

This study investigates the overnight air infiltration rates of 202 natural ventilated bedrooms, measured in August to September 2016 (cooling season) in Guangzhou, China. The rates were calculated and analyzed based on a single zone mass balance equation, using CO2 produced by the sleeping occupants as tracer gas source. It was found that additional ventilation is required to satisfy the Chinese building code, where only 16% had the minimum required amount of ventilation. The air infiltration rates fit a log-normal distribution (R2 = 0.85) ranging from 0.05 to 1.32 h−1, with an arithmetic mean of 0.41 h−1. None of these parameters had an effect on the air infiltration rate distribution: Absolute indoor and outdoor temperature difference, window age, building type (two different window standards), floor level of bedroom and openable window area. The provided data can be used in analyzing cooling energy and indoor air quality from outdoor pollution in natural ventilated residential buildings in south China.

Thermal comfort is one of the key factors affecting human sleep. This study aimed to provide new understandings on sleep thermal comfort in residential environments by investigating the characteristics of behavioral adjustments and exploring the relationship among indoor thermal environment, bed microclimate and sleep thermal comfort. Both online and field surveys were conducted in China. Two large-scale online questionnaire surveys were carried out in winter and summer, a total of 4127 valid samples were collected. The field study was conducted in 14 bedrooms and was divided into two periods in summer and winter, each period lasted for 2–3 weeks. The field study involved continuous monitoring of bedroom air temperature, bed temperature and daily collection of post-sleep questionnaires and collected 461 valid samples. Based on the collected data, people’s adjustments of bedding systems in different indoor environments were analyzed systematically from several aspects, including the components on both the covering side and the underlying side, the coverage forms, the total thermal insulation of bedding systems. The use of two heating modes during sleep (space heating and bed heating) were investigated and the effects of regional and personal factors on the usage were explored. Under the influence of behavioral adjustments, thermal sensation during sleep was found to be weakly correlated with overnight bedroom air temperature, bed temperature was not correlated with overnight bedroom air temperature.

Summertime overheating in care settings has been identified as a key risk and research priority for the health and social care system. This paper examines the current and future risk of summertime overheating in two London-based care homes occupying modern and older buildings. Continuous monitoring of outdoor and indoor temperature in bedrooms, communal areas and offices in summer 2019 helped to establish the prevalence and intensity of overheating. Dynamic thermal simulation (EnergyPlusV8.9) of the two care settings assessed the potential for avoiding active cooling in future climate using passive solutions. In both care settings, indoor temperatures were observed to exceed 30 °C during daytime hours, significantly higher than the recommended 26 °C threshold of Public Health England. Although severity of overheating was lower in the older building, overheating was found to be prevalent and prolonged across both care settings with bedroom temperatures higher than lounges especially at night. Thermal simulation analysis showed that, with regards to temperature reduction and cooling load, nighttime ventilation was the single most effective passive solution for both buildings for the current climate, while a combination of night ventilation, external shading and high-albedo external walls was the most effective package solution. By the 2080s, air-conditioning was the most effective solution for reducing temperature, but also had the highest cooling load, highlighting the importance of balancing passive with active measures to improve thermal comfort and reduce cooling loads.

Due to the increased expectations on human thermal comfort in sleeping environments at a low energy consumption, task/ambient air condition system (TAC) can be the best air conditioning method when considering the immobility of a sleeping person. Previously, convection-based TAC systems for sleeping environments were developed, with an obvious inadequacy of cold-draft problem. Therefore, a new radiation-based TAC system (R-TAC) was previously developed and experimentally studied at a set of fixed design parameter for its radiant panel. Therefore, a follow-up numerical study on the effects of varying design/operating parameters of the radiant panel on indoor thermal comfort and energy saving performances has been carried out, and the study results reported in this paper. Firstly, a geometry model based on the experimental bedroom used in the previous experimental study, boundary conditions and numerical study cases are detailed. Secondly, the results of validating the numerical method using the previous experimental data are reported. Thirdly, the numerical results on indoor thermal comfort, energy saving and draft risk at different surface temperature and emissivity, area of the radiant panel, and the distance between the radiant panel and a bed are presented. The numerical results demonstrated that all the four design/operating parameters of the radiant panel can significantly affect thermal comfort and energy saving performances in the bedroom when using the R-TAC system: increasing surface temperature can lead to a higher PMV value and a higher EUC value; increasing surface emissivity and area of the radiant panel a lower PMV value and a lower EUC value; reducing the distance between the bed and the panel a lower PMV value and a higher EUC value. Finally, the DR values were at a very low level in all the study cases, indicating the cold draft problem encountered when using a convective heat transfer based TAC system for a sleeping environment can be effectively resolved when using the R-TAC system.

Thermal environment in bedrooms is still a largely neglected topic in thermal comfort research, although a thermal comfortable environment is important for sleep maintenance. Studies confirm that human body is sensitive to air temperature during sleep; even moderate heat or cold exposure decrease sleep quality significantly. In the present paper we reviewed air temperatures measured in bedroom and the effects of heat and cold exposure on sleep quality, and then proposed 5 aspects of approaches or technologies that could improve sleeping thermal environment at a low energy consumption. We concluded that there are two important research topics in sleeping thermal environment. One is to develop sleeping-mode control strategy for air conditioner used in bedroom to get slight increase or to avoid decrease in room air temperature when approaching morning. The other is to control bed micro-environment energy efficiently by using of local heating, cooling and/or ventilation system.

To validate the feasibility of Actiwatch 2 (AW2) to measure sleep quality in thermal comfort researches, five parameters drawn from AW2 and the subjective evaluation of sleep quality, sleep quality vote (SQV) were collected. Furthermore, to explore the effect of thermal environment and IAQ on sleep quality with AW2, the standard effective temperature (SET) was induced to evaluate the integrated effect of the sleeping thermal environment and CO2 was to indicate the freshness of air quality. Ambient temperature, relative humidity, mean radiant temperature, air velocity and CO2 concentration were monitored in 6 bedroom of different type, including natural-ventilated rooms and air-conditioned rooms, during the hot season in Beijing for nearly one month. The occupant bedding system, posture habit and thermal sensation vote before sleep (BTSV) and after sleep (ATSV) of 3 female and 3 male subjects were recorded with questionnaire. The results showed that some of the sleep quality parameters measured by AW2 accorded with the subjective evaluation; Thermal environment had an effect on sleep quality according to the significant correlations between SET and the sleep quality parameters measured by AW2; The thermoneutral range of SET in sleeping condition was between 29.1–29.7 °C, based on which the thermal insulation of bedding system (Icl) was recommended to be 0.96–1.08 clo.

Bedroom air-conditioning is often programmed to cause the air temperature to follow either a Rise-Fall or an inverted Fall-Rise shaped course during the night, and there are rational arguments for both. The effects of these two programmed air temperature changes were investigated by creating three thermal conditions: a reference condition with constant temperature (26 °C), a Rise-Fall change condition (26 °C–27 °C–28 °C–27 °C–26 °C), and a Fall-Rise change condition (28 °C–27 °C–26 °C–27 °C–28 °C). Twelve healthy young people (6 females and 6 males, mean age 23 years) slept in a climate chamber with multiple of their physiological parameters monitored continuously. No significant difference in thermal comfort or sleep quality was found among the three conditions. The subjects had better next-day performance in the Fall-Rise condition than in the other two conditions. Simulation results show that compared with the reference condition, the total cooling load of a simulated bedroom is reduced by 27.8% in the Rise-Fall and 34.3% in the Fall-Rise condition. These results indicate that a slight increase of air temperature within thermal comfort range during the later period of sleeping (as simulated in the Fall-Rise condition) could better prepare the body for wake up, and also could save energy.

Occupant presence and behavior can and should influence energy use in buildings. If occupancy is measured, predicted, or otherwise inferred, building controls can automatically adjust system operating parameters to use less energy without sacrificing user services. However, previous field evaluations and simulation studies appear to have overestimated the energy savings associated with this type of smart control. In this article we present results from a carefully controlled field evaluation of occupancy-responsive learning thermostats installed in every bedroom of three high-rise university residence halls. While a standard practice energy model developed prior to the retrofit estimated 10–25% savings for cooling and 20–50% savings for heating, measurements reveal that the control scheme only reduced energy consumption by 0–9% for cooling, and by 5–8% for heating for normal operation during academic periods. However, for non-academic periods when the residence halls were sparsely populated, the scheme reduced cooling energy consumption by 20–30%. We analyzed these observations in relation to occupancy patterns, room temperature records, ambient conditions, and equipment run time. The findings provide novel insight about how to improve field evaluations and refine model assumptions to better predict the impact of occupancy-responsive thermostat controls. Notably, while analysts often use fractional building occupancy trends to simulate building energy performance, this study highlights the importance of accounting accurately for both the temporal and spatial variation of vacancy events throughout a building.

The implementation of mechanical ventilation systems with heat recovery (MVHR) in new high-performance residential buildings constitutes a fundamental change from traditional heating and ventilation strategies. A MVHR with one ventilation zone, which is commonly used in new residential buildings, will supply approximately the same temperature to all rooms and consequently contribute to balancing the room temperatures within the dwelling. This change affects air change rates, the air distribution between rooms and temperatures, and consequently calls for an evaluation of the impact on the perceived and actual indoor climate and of to what degree the desired indoor climate conditions are provided. Therefore, a post-occupancy evaluation (POE), consisting of a user survey and long-term measurements, is performed for a high-performance residential project in Norway. The results support earlier findings that indicated an improved indoor climate in high-performance residential buildings with MVHR compared with other building standards. However, the findings clearly demonstrate a need for temperature zoning in residential buildings. The preferred lower bedroom temperatures appear to be difficult to achieve in common high-performance building concepts with MVHR. An important factor that influences bedroom temperatures was found to be the control strategy for the supply air temperature, where a potential for improvement was observed.

More and more studies reported that there were insufficient ventilation and excessive CO2 concentration in air-conditioned residential buildings, but few solutions were provided. This study investigates the overnight evolution of CO2 concentration in air-conditioned residential buildings and then focuses mainly on the evaluation of three ventilation strategies, including overnight natural ventilation, short-term mechanical ventilation and short-term natural ventilation. On-site measurements were conducted in a typical residential bedroom in Hong Kong in September. The indoor and outdoor CO2 concentration, air temperature and relative humidity as well as the outdoor wind speed during the measurements were analysed. Ventilation rates were calculated based on the time series of CO2 concentration. This study confirms that additional ventilation is usually needed in air-conditioned residential buildings. Overnight natural ventilation with even a small opening is associated with excessive energy consumption and deteriorated indoor thermal environment. Short-term natural ventilation strategies are inefficient and uncontrollable. Compared to the best short-term natural ventilation strategy, a reasonably designed short-term mechanical ventilation strategy requires only a 41% of ventilation period to complete one full replacement of indoor air and to reach a lower indoor CO2 concentration. Nighttime case studies and a theoretical analysis suggest that a few several-minute mechanical ventilation periods could potentially maintain an acceptable indoor air quality for a normal sleeping period of 8 h.

In the subtropics, air conditioning (A/C) for a bedroom in residential buildings commonly serves to provide an appropriate indoor thermal environment at nighttime for sleeping. During daytime when A/C is not provided, a large amount of thermal energy can be stored in the thermal mass in its envelope components, in particularly its external walls. The energy stored would be gradually released, contributing significantly to the total space cooling load in the bedroom at nighttime. Therefore, this paper reports a simulation study on the impacts of daytime external envelope heat gain/storage on the nighttime cooling load in a hypothetic west-facing bedroom and the related mitigation measures in the subtropical Hong Kong. The study results showed that, among all envelope components, the west-facing external wall contributed most significantly to the total nighttime cooling load, because of its direct exposure to solar radiation, thus the heat gain and storage in its thermal mass. In addition, adding an air gap in the west-facing external wall can reduce remarkably the hourly total nighttime cooling load for the first hour (21:00–22:00) and the total cooling load for the 10-h A/C period. However, while varying the width of either the air gap or inside/outside concrete layers would not reduce cooling load further, ventilating mechanically the air gap can further increase the cooling load reduction and improve the flatness of load variation profile at the expense of consuming additional electrical energy. Finally, adhering aluminum foil to both sides of the air gap can further remarkably reduce nighttime cooling load, and improve the flatness of the load variation profile.

The increasing demand for improving indoor thermal environment in the hot summer and cold winter climate zone (HSCW) in the Yangtze River region in China poses enormous challenges in terms of energy policy and design solutions for this unique region. A comprehensive understanding of people’s habits and behaviors involving winter heating is imperative for decision making for urban heating infrastructure investment strategies that significantly impact the decarbonization of heating. However, there are little studies of a large-scale survey to gain such knowledge acrose the region. The aim of this study is to develop a rigorous survey method in order to obtain reliable data for analysis. Five municipal/capital cities across the upper, middle and downstream Yangtze River were surveyed based on 30 randomly generated locations in each city. A total of 8481 valuable samples were obtained in the survey conducted in the winter from November 2017 to March 2018. It is revealed that air conditioning/air source heat pumps are the predominant systems, accounting for 63% and 58% for bedroom and living room heating respectively. The use patterns of heating are diverse featuring ‘part-time-part-space’ systems in accordance with the occupancy patterns. There is significant evidence of the habit of opening a window to provide a gap for fresh air irrespective of whether the heating is in use. Two-step cluster analysis is employed to subdivide occupants’ heating-related behaviors into three clusters to characterize households. This study fills the knowledge gap of winter-heating-related behaviors. The research outcomes will benefit building energy simulations for energy prediction and help policy makers making decisions on providing strategic guidance in terms of winter heating solutions in this region.

Since aging is associated with a progressive decrease in thermoregulation, a cold bedroom environment may have negative effects on the sleep quality of the elderly. This study investigated the effects of two bed heating methods (covering heating and mattress heating), compared with no heating, on sleep quality of the elderly without sleep disorders in a cold environment. Twelve elderly who did not use any heating in daily life participated into this field intervention experiment, which was performed in their own bedrooms. Sleep quality was subjectively evaluated using questionnaires in the morning and objectively measured with a wristband which continuously monitored throughout the sleep period. Skin temperatures and blood pressure were measured. The subjects felt thermally comfortable when slept in all conditions. Compared with no heating, covering heating and mattress heating increased the total sleep time by 35.5 min and 20.3 min, and decreased the sleep onset latency by 13.3 min and 18.3 min. Compared with mattress heating and no heating, the covering heating decreased the wake after sleep onset by 28.7 min and 12.5 min, and increased the sleep efficiency by 2.8% and 5.7%. Both two heating methods increased the bed temperature and reduced the skin temperature gradient between the chest and calf. The systolic blood pressure measured in the morning was significantly lower in the covering heating than in no heating. These results suggest that, without changing thermal comfort, bed heating improved micro thermal environment, sleep quality and health of the elderly without sleep disorders in a cold environment.

Recently, the construction of energy efficiency buildings has been one of the main objectives of sustainable development, especially for areas with extreme climate. In present study, the adaptive thermal comfort and climate responsive strategies in dry–hot and dry–cold areas were investigated with field measurement and questionnaire in the Turpan basin, China. First, the adaptive thermal comfort model was established to reveal the relationship between indoor thermal comfort conditions and outdoor climate. Then, the climate responsive strategies which helped residents adapt to harsh climate were concluded. The prototype of climate responsive dwellings is proposed. Finally, the effects of these strategies were investigated by field measurement of indoor thermal environment in two demonstration houses and evaluated by the proposed thermal comfort model. The results showed that residents in the Turpan basin exhibited better adaptability to the hot climate than the cold climate with the upper limits of 80% acceptability reaching 34 °C. The heavy structure envelope and constructional patterns based on the thermal adaptive behaviors of residents could improve indoor thermal environment. In summer, semi-basement was the most effective strategy to satisfy human thermal comfort, followed by night ventilation. The indoor air temperature in semi-basement was around 31 °C while outdoor temperature exhibited diurnal variation of 15.7 °C from 28.6 °C to 44.3 °C. In winter, passive solar heating and semi-basement were both effective. The indoor air temperature was higher in the bedroom located at the south semi-basement compared with other rooms. The study can provide new thoughts for designing climate friendly buildings in dry-hot and dry-cold areas.

Natural ventilation in residential buildings has a great potential for conserving energy and improving the health of occupants. This paper first presents a design strategy for optimizing natural ventilation in high-rise residential buildings in Chongqing, China, a region with unfavorably low wind speed. Through the use of CFD modeling, building orientation and spacing were adjusted, wind paths were created into internal zones, and two windows were constructed in each bedroom. The optimized design reduced the age of air to less than 6 min in 90% of the rooms, as compared to an age of greater than 30 min in 50% of the rooms in a conventional design. Natural ventilation was found to be effective in the Chongqing area with the optimized design. This investigation also measured the local age of air and air change rate in a building with the optimized design using a tracer-gas method. The measurements confirmed the reliability of the CFD results.

Because of the increased expectations on thermal comfort and indoor air quality in sleeping environments at a low energy consumption, it is necessary to develop new air conditioning systems applied to sleeping environments. In recent years, a large number of studies on task/ambient air conditioning (TAC) have been carried out due to its excellent ventilation and energy saving performance. However, compared to full volume air conditioning (FAC), there exists an inadequacy on thermal control for TAC because cooled air is directly delivered to the space around a human body. Hence, the TAC and FAC systems have their own pros and cons in aspects of thermal, ventilation and energy saving performances, and the position of a supply outlet in an air conditioning (A/C) system significantly influences its operating performances. Therefore, a study on the performance evaluations of an A/C system installed in an experimental bedroom with its supply outlet positioned at five different heights has been carried out, and the study results are presented in this paper. The study results suggested that overall speaking, the A/C system performed the best at a supply air temperature of 23 °C, an air flow rate of 50 L/s and a fresh air flow rate of 13 L/s at H1100 setting, among all study cases. On the other hand, the A/C system performed the best at H800 setting among the five height settings.

Expert guidance in the UK suggests a limit to temperatures in bedrooms to of 26 °C or less to avoid overheating. This short paper looks at the temperatures in bedrooms and uses data from comfort surveys combined with models which link comfort to the thermal environment. Evidence is given that people sleep comfortably where temperatures are 29–31 °C in their personal space within the bed and they use bedclothes to allow them to attain these temperatures. The effect of the use of a mattress and the adaptive opportunities afforded by the bedclothes and sleepwear are briefly explored as are methods used in hot climates to offset high bedroom temperatures.

Residential buildings are typically associated with high energy consumption, especially because of air-conditioning (AC) usage. Occupant behaviour can noticeably affect how an AC operates and thereby contribute to the increasing energy consumption. This problem is more pronounced with the split-type air-conditioner that is popular in South China. This study identified three representative patterns related to occupancy and AC on/off settings according to AC operation recordings from 102 bedrooms in several residential buildings of metropolitan Guangzhou, South China. Bedroom AC operation details were recorded using individual smart socket units. The resulting data showed clustering for daily on/off times, the duration of each operation, and AC ‘run-over-night’ probability. These clusters revealed three user-configuration patterns (i.e. night-time AC usage only (49%), both night-time and noon AC usage (6%), and low AC usage (45%)). Occupant age, total floors, and room area indices were most closely related to occupant behavioural patterns. Results indicated that AC units should be ‘turned on’ in timed steps when operation rates are higher than 30% or 20% to achieve acceptable thermal comfort performance. These findings should be useful for those intending to reduce overall energy consumption because the analysed schedules were based on realistic usage rather than conventional assumption (i.e. the full-time/full-space usage).

This study investigated the determinants of the proportion of hours a dwelling meets the indoor temperature threshold for healthy living of at least 18 °C in winter, as recommended in a recent review. Secondary data analysis of a nationally representative survey of English homes (N = 635) showed that older dwellings, detached homes, single occupancy and living in the North of England are associated with the lowest share of hours at the recommended temperature threshold in bedroom, living room, and hallway. These identified determinants could be used to target households at greatest risk of ‘unhealthy’ temperatures. Being aged above 64 and having a disability is linked to more hours at the criterion; an encouraging finding that the most vulnerable experience low temperatures to a lesser extent. This study also highlights the need for further research particularly in relation to those variables where results were equivocal and / or there was weak supporting evidence, such as tenure, wall type, and EPC rating.

In this study a Building Information Model (BIM) tool is developed to simultaneously estimate embodied and operational carbon over a 60 year life span for a typical four bedroom detached house. Using the tool, four different construction scenarios are evaluated, representing a range of current construction methods used in present day UK house building. The results show that cradle-to-gate embodied carbon represents 20–26% of the total 60 year carbon emissions, with operational carbon representing 74–80% of total emissions. Construction scenarios that reduce operational carbon by improving the thermal envelope led to a 1–13% increase in embodied carbon but a 4–5% decrease in operational carbon compared to the basecase construction method. Approaches to reduce embodied carbon in new-build housing are also studied and a 24% reduction is demonstrated through building fabric changes. The study recommends that a universally robust methodology for measuring embodied carbon will enable design decisions to be taken to reduce whole life carbon emissions through improved choice of materials. Due to material changes impacting on the thermal characteristics of a dwelling, and to an extent the structural characteristics, an integrated BIM tool will be essential in quickly establishing whole life carbon impacts during the design stage.

The monitored performance of the first new London dwelling certified to the Passive House standard is presented. The first detailed analysis of the energy consumption of the heating, ventilation and domestic hot water systems are given. The annual space heating demand of the 2 bedroom, 101 m2 dwelling was 12.1 kWh/m2, achieving the 15 kWh/m2 Passive House target. The annual primary energy demand was 125kWh/m2, marginally above the 120 kWh/m2 target. The measured internal heat gains of 3.65 W/m2 are much greater than the 2.1 W/m2 suggested as standard for dwellings. The Passive House Planning Package, PHPP, is found to be a good predictor of space heating demand and the risk of summer time over heating. Winter space heating demand is sensitive to occupant blind use. With a total metered energy consumption of 65 kWh/m2, the Camden Passive House is one of the lowest energy, small family dwellings, monitored in the UK.

Vernacular residential houses in Thailand were not heated nor cooled. The walls of such houses were constructed from wood and other light natural materials. Air-conditioning to cool interior spaces is now common and brick and concrete has replaced natural materials for walling. Even when a house is designed for air-conditioning, no insulation is used on the enclosing walls. It is generally believed that thick and heavy walls reduces cooling load in a space but insulation may not and is too costly. This paper presents results from an experimental and simulation study on comparative thermal performance of walls enclosing spaces that are used to serve three residential functions of bedroom, living room, and studio room. The study considers different levels of insulation and its placement at the interior and exterior surfaces on walls with and without windows, and for each functional use of a space. Use of external shading and blinds or curtain is not considered in this study. In all cases, the study concludes that insulation placed at interior wall surface improves wall thermal performance and is superior to that of exterior placement. The latter part appears to contrast with what have been found in similar studies taken under cool climate.

There are growing concerns that the move to lightweight building construction in housing will lead to higher internal temperatures during the summer, particularly in the warmer future, due to lack of thermal mass. A dynamic thermal simulation study using Tas EDSL undertaken by Oxford Brookes University compared the thermal performance of current light, medium and heavy construction techniques for a typical UK three bedroom house. It found little difference in overheating performance for the three constructions in 1990s and 2050s (projected) weather scenarios. It is concluded that current practice in house building concedes little advantage to ‘traditional’ over modern construction techniques. Thermal mass can reduce overheating, primarily in the daytime, but it must be properly exploited by good design (good night ventilation, correct materials in the correct places). It is suggested that it is possible to optimise lightweight housing to provide similar thermal comfort levels during occupied hours using ventilation and shading.

A lack of empirical data for residential indoor temperature has important implications for policy-makers in terms of energy performance objectives and the use of energy demand models for the building stock. This study investigates winter indoor temperatures, relative humidity and vapour pressure excess in 2009-2010 across various types and ages of buildings using half-hourly monitoring of 96 dwellings representative of residential buildings in Belgrade, including those with district heating (DH) with no direct occupant control in which heating is charged on a floor area basis. The average daily living room temperature of 22.8 degrees C (95%CI: 21.9-22.7) in DH dwellings was 2.3 degrees C higher than those with other heating types, including individual central heating (ICH) and non-central heating (non-CH), daily bedroom temperature of 22.3 degrees C (95%CI: 21.9-22.7) was 3.0 degrees C higher. Evening living room and night bedroom temperatures in ICH dwellings were 22% and 37% of the time respectively below 18 degrees C, and 10% and 27% of the time respectively in non-CH dwellings. The high degree of overheating in DH dwellings indicates the considerable potential to reduce energy consumption, if user controls and heating bills reflected household consumption were introduced. (C) 2012 Elsevier B.V. All rights reserved.

In the past decade, the application of phase change material (PCM) wallboard in building facade has gained wide attention around the world. For successful application of PCM integrated building facade, a number of crucial factors including thermo-physical properties of PCM, outdoor climate condition, operating schedule of building, investment cost and tariff structure should be taken into account. In this study, a typical residential flat with PCM integrated external walls constructed in the living room and bedroom was modeled and the thermal/energy performance was investigated. The effect of PCM integrated wall's orientation was also evaluated. Through computer simulations, it was found that the living room of a residential flat with west-facing integrated external wall could perform better. It gave a comparatively higher decrease in the interior surface temperature up to a maximum of 4.14%. Moreover, an annual energy saving of 2.9% in air-conditioning system was achieved. However, a long cost payback period of 91 years makes the PCM integrated building facade economically infeasible. On the other hand, the energy payback period was estimated as 23.4 years for this building case, indicating that the energy saving can surpass the embodied energy of PCM wallboard and mitigate the greenhouse gas emission.

The aim of this study is to examine the effect of a major domestic energy efficiency refurbishment programme on domestic space heating fuel consumption. The case study dwellings were monitored either before or after (or both) the introduction of energy efficiency retrofit measures such as cavity wall insulation, loft insulation, draught stripping and energy efficient heating system. Property and utility consumption data were collected and half-hourly living room and main bedroom temperatures were monitored for 2-4 week period over two winters from a total of 1372 households selected from five major urban areas in England. Space heating fuel consumption was normalized to account for variation in the indoor-outdoor temperature difference and the dwelling floor area. The findings show that cavity wall and loft insulation can reduce the space heating fuel consumption by 10% in centrally heated properties and 17% in non-centrally heated properties. However, the introduction of a gas central heating system, although theoretically more efficient, has no significant impact in reducing fuel consumption even after adjusting for increased internal temperature. (C) 2006 Elsevier B.V. All rights reserved.

The objective of this study is to quantify the extent to which variation in heating season indoor temperatures is explained by dwelling and household characteristics and increased by energy efficiency improvements in low income households. A survey of dwellings in the Warm Front home energy efficiency scheme was carried out in five urban areas of England. Half-hourly living room and main bedroom temperatures were recorded for 2-4 weeks over two winters. For each dwelling, regression of indoor on outdoor temperature was used to obtain estimates of daytime living room and night time bedroom temperatures under standardized conditions (outdoor temperature of 5 degrees C. The results indicate that the median standardized daytime living room temperature was 19.1 degrees C and the median standardized night time bedroom temperature 17.1 degrees C. Temperatures were influenced by property characteristics, including its age, construction and thermal efficiency and also by the household number of people and the age of the head of household. Dwellings that received both heating and insulation measures through the Warm Front scheme had daytime living room temperatures 1.6 degrees C higher than pre-intervention dwellings, night time bedroom temperatures were 2.8 degrees C higher. Warm Front energy efficiency improvements lead to substantial improvements of both living room and bedroom temperatures which are likely to have benefits in terms of thermal comfort and well-being. (C) 2005 Elsevier B.V. All rights reserved.

Majority of residential apartments in Hong Kong may be equipped with up to three window-type air-conditioners that operate during 7 months of hot and humid weather. The units are placed in the living rooms and bedrooms. The positions of these units and furniture inside these small rooms are directed in some extent by the architectural design, however, residents have possibility to decide about their actual position. The occupants should locate their air-conditioner with respect to the room furniture to avoid the cold air re-circulation and draft, and to obtain good thermal comfort for residents. To accomplish this, flat manufacturers should give some recommendations to the occupants, and architects should include such concerns in their design. For three positions of an air-conditioner unit and one position of a bed and a cupboard in a typical Hong Kong residential bedroom, the air velocities, temperatures, and air diffusion performance index are determined by using the computational fluid dynamics (CFD) software FLOVENT. The cases with the maximum benefit and maximum consequences in terms of thermal comfort in the bedroom are identified.

A CO 2 concentration of more than 1000 ppm has been monitored in Taiwanese bedrooms during sleeping hours in the wintertime. The high indoor CO 2 levels were caused by poor ventilation due to insufficient ventilation rates. This study sought to reduce the wintertime CO 2 concentration level in a typical Taiwanese bedroom with less outdoor air to maintain thermal comfort. CO 2 was used as an indicator to assess whether an adequate ventilation rate has been obtained to dilute or remove harmful pollutants. With the help of the thermal buoyancy effect, the CO 2 generated in the bedroom was effectively removed by means of less outdoor air. Through computational fluid dynamics simulations, the appropriate window and transom locations with the corresponding outdoor air supply volume, as well as the lowest possible outdoor air temperature were identified.

The LTEE laboratory of Hydro-Quebec, in collaboration with Canada Mortgage and Housing conducted an indoor air quality study involving 30 single family-detached houses heated with electric baseboard heaters in the vicinity of Trois-Rivieres during the 1993–1994 heating season. The houses were selected according to the measured air leakage at 50 Pa so as to have a sample distribution similar to the distribution of air leakage of houses in the province of Quebec. The ‘source strength’ of several air pollutants were calculated from measurements of ambient pollutant levels and total ventilation during a 1-week test. In addition, the indoor CO 2 and humidity levels were recorded in eight of the houses continuously during the heating season. Model studies using the measured pollutant source strenghts and measured equivalent leakage areas of the buildings indicated that the recommended health guidelines for airborne respirable solid particles (RSP's), CO 2 and formaldehyde are exceeded during periods of low total ventilation, coinciding with mild outdoor temperatures and low wind conditions. With the room occupied and the door closed, CO 2 levels in the bedroom increased steadily during the night until morning, when the door was opened, to levels in excess of 3500 ppm with one person and in excess of 4500 ppm with two persons. Various different methods of ventilating some of the houses were tested, including quiet replacement exhaust fans, mixing fans for indoor air and a fresh air intake and mixing system. The effects of operating various air handling systems were monitored by keeping track of indoor CO 2 and relative humidity in the master bedroom and occupancy in person-hours per day.

Differences between measured and predicted energy demand of dwellings across construction age-bands are of interest since these categories mark changes in construction methods and building codes over time. This study compared empirical measures of gas consumption for three-bedroom dwellings in the UK with predictions from the Cambridge Housing Model (CHM), a bottom-up building physics model used for national energy statistics and government policy development. It used gas consumption data collected from 2008 to 2010 from a sample of 255 three-bedroom dwellings. For age-bands of dwellings built since 1919, empirical estimates of annual gas consumption in 2011 were slightly higher than the model predictions but the rate of decline across age bands matched the model closely. For dwellings built before 1919, which are characterised by solid wall construction, the empirical estimates were markedly lower than the model predictions both for annual gas consumption and the Power Temperature Gradient (W/K) – a first order estimate of energy performance from monthly data. These findings have implications both for development of energy models and for policy regarding energy efficiency programmes, since they suggest retrofit of older dwellings will result in lower energy saving than predicted by current building physics models.