The effect of indoor environmental quality on occupants’ perception of performance: A case study of refurbished historic buildings in Malaysia

This paper presents an assessment of occupants’ opinion of the internal environment of buildings, based upon their responses to questions relating to a range of discrete factors. The survey considers many aspects of the internal environment and seeks to gain occupants responses to each of these in terms of “User Satisfaction” and “Degree of Importance”. The questionnaire utilised a seven-point bi-polar scale to score these responses against each of the factors. In addition, the questionnaire elicits a ‘fingerprint’ that combines up to 22 factors relating to satisfaction with the building. The study documents and considers aspects of the building environment for which the users noted that they were least satisfied as well as those that are considered by the occupants as being of most importance. It is critical that sustainable development results not just in resource conservation, but also in increasing productivity and occupant well-being within buildings. This study hopes to provide insight for the design community on the perceptions of occupants in relation to building performance based on indoor environmental quality (IEQ) criteria. It also seeks to add to the growing body of research on sustainable design and occupants’ perception of IEQ.     

夏热冬暖地区绿色建筑性能后评估研究

为了解夏热冬暖地区绿色建筑运行后实际能耗和室内环境品质，文章详细介绍了该气候区内绿色建筑主要技术的应用情况及应用效果。选取位于该气候区内共11个获得绿色建筑认证的办公建筑，通过调研实际能耗，结合用户主观问卷调研，与常规办公建筑的能耗和室内环境品质主观满意度进行了对比研究。结果表明，对于A类办公建筑，绿色建筑与常规建筑无明显差异，均略低于引导值；对于B类而言，绿色办公建筑的总能耗显著低于常规办公建筑，但与能耗指标相比二者能耗均较高，是建筑节能工作的重点。在室内环境品质满意度方面，用户对绿色建筑的满意度明显高于常规建筑，在空气品质和室内环境控制上尤为明显，光环境的差异则更多是归因于天然采光的设计，而非人工照明的优化。最后通过一个案例从节地、节能和室内环境等3个方面全面地介绍了适宜于夏热冬暖地区的绿色建筑设计。     

Post occupancy evaluation of green residential buildings,in the Greater Kuala Lumpur,Malaysia

Homebuyers are now demanding green buildings over conventional buildings due to better performance, higher operating savings, and the premium satisfaction that the green buildings offer. However, whilst the supply of green buildings is increasing, the satisfaction of the occupants requires evaluation. This research investigated the satisfaction of the occupants of certified residential green buildings in the Greater Kuala Lumpur. The research was based on a cross-sectional survey questionnaire comprising 15 performance factors and 118 green building occupants. The survey forms were administered through hand delivery. The satisfaction of the occupants with respect to the ability of the buildings to accommodate the elderly and the disabled was very high. The occupants were also satisfied with the acoustics, overall lighting, layout, and overall air quality of the buildings. The factor analysis structured the performance factors into four clusters, namely, lighting, indoor environmental quality, operating cost, and spatial. The findings will be useful for the design teams because developers and city planners and the green rating certifiers and facilitators make their decisions on the prioritisation of the performance criteria of the green buildings. Whilst the data were collected in Malaysia, the information is applicable to beyond Malaysia.

     

Self‐reported health and comfort in ‘modern’ office buildings: first results from the European OFFICAIR study

In the European research project OFFICAIR, a procedure was developed to determine associations between characteristics of European offices and health and comfort of office workers, through a checklist and a self‐administered questionnaire including environmental, physiological, psychological, and social aspects. This procedure was applied in 167 office buildings in eight European countries (Portugal, Spain, Italy, Greece, France, Hungary, the Netherlands, and Finland) during the winter of 2011–2012. About 26 735 survey invitation e‐mails were sent, and 7441 office workers were included in the survey. Among respondents who rated an overall comfort less than 4 (23%), ‘noise (other than from building systems)’, air ‘too dry’, and temperature ‘too variable’ were the main complaints selected. An increase of perceived control over indoor climate was positively associated with the perceived indoor environment quality. Almost one‐third of office workers suffered from dry eyes and headache in the last 4 weeks. Physical building characteristics were associated with occupants’ overall satisfaction (acoustical solutions, mold growth, complaints procedure, cleaning activities) and health (number of occupants, lack of operable windows, presence of carpet and cleaning activities). OFFICAIR project provides a useful database to identify stressors related to indoor environmental quality and office worker's health.     

Energy efficient design and occupant well-being: Case studies in the UK and India

The purpose of this paper is to demonstrate the relationships between sustainable building design and occupant well-being. It starts with a definition of sustainable design and well-being, and focuses on the relationships between energy performance and occupant feedback. Methodologically it draws on detailed monitoring and surveys of 12 case study office buildings in the UK and India, and the paper uses the data to explore whether energy use and associated CO₂ emissions are correlated to occupant satisfaction and comfort. The results demonstrate that increased energy use in the case study buildings is associated with increased mechanisation (e.g. centralised air conditioning) and reduced occupant control. This reduced control in turn is shown to relate to reduced occupant comfort and satisfaction. Finally, the paper reveals that the reported health conditions of occupants correlates strongly with their levels of satisfaction. The overall conclusion is that energy use in typical office buildings is inversely correlated with the well-being of the occupants: more energy use does not improve well-being.     

Indoor air quality in energy‐efficient dwellings: Levels and sources of pollutants

Worldwide, public policies are promoting energy‐efficient buildings and accelerating the thermal renovation of existing buildings. The effects of these changes on the indoor air quality (IAQ) in these buildings remain insufficiently understood. In this context, a field study was conducted in 72 energy‐efficient dwellings to describe the pollutants known to be associated with health concerns. Measured parameters included the concentrations of 19 volatile organic compounds and aldehydes, nitrogen dioxide, particulate matter (PM_2.5), radon, temperature, and relative humidity. The air stuffiness index and night‐time air exchange rate were calculated from the monitored carbon dioxide (CO₂) concentrations. Indoor and outdoor measurements were performed at each dwelling during 1 week in each of the two following seasons: heating and non‐heating. Moreover, questionnaires were completed by the occupants to characterize the building, equipment, household, and occupants’ habits. Perspective on our results was provided by previous measurements made in low‐energy European dwellings. Statistical comparisons with the French housing stock and a pilot study showed higher concentrations of terpenes, that is, alpha‐pinene and limonene, and hexaldehyde in our study than in previous studies. Alpha‐pinene and hexaldehyde are emitted by wood or wood‐based products used for the construction, insulation, decoration, and furnishings of the dwellings, whereas limonene is more associated with discontinuous sources related to human activities.     

Multitrait-multimethod analysis of subjective and objective methods of indoor environmental quality assessment in buildings

Indoor environmental quality (IEQ) refers to the condition of a building’s internal environment that is related to the occupants’ health, comfort, and wellbeing. The assessment and improvement of IEQ in buildings are based on either subjective or objective assessment or the use of both measures, and in recent times, have been attracting attention due to its role in contributing to green building and sustainable environment. This study is aimed at evaluating and analysing the validity of the IEQ parameter traits as assessed using subjective and objective measures. The convergent and discriminant validity of the measured parameter traits were tested by analysing a multitrait–multimethod (MTMM) matrix using confirmatory factor analysis (CFA). The results indicated that there is no convergent validity in the IEQ parameter traits as assessed using subjective and objective methods. However, discriminant validity of the measured parameter traits was adequately supported. This clearly shows that as much as IEQ parameter traits measured through objective physical measurement and subjective occupant survey define the same concept, they cannot be taken to represent a single and same unit of measurement.     

Indoor environmental quality differences between office types in LEED-certified buildings in the US

The study compared IAQ, thermal quality, and lighting quality between 5 different office types in LEED-certified buildings in relation to employees' environmental satisfaction and their job performance. This was to provide workplaces where workers in each specific office environment could be provided with appropriate office settings regarding these IEQ criteria when organizations comply with LEED standards. The five types of office included private enclosed, private shared, open-plan with high cubicle over 5′, open-plan with low cubicle lower than 5′, and open-plan with no partitions (bullpen) offices. The study found IAQ enhanced workers' job performance in enclosed private offices more than both high cubicles and low cubicles. All four office types had higher satisfaction with the amount of light and visual comfort of light as well as more enhancement with job performance due to lighting quality than high cubicles. There was no difference in thermal quality between the five office types. IAQ and lighting quality were not different between enclosed private, enclosed shared, and bullpen office types, either. The study findings suggest a careful workplace design considering the height of partitions in LEED-certified buildings to improve employee's environmental satisfaction and job performance.     

A comparison of occupant comfort and satisfaction between a green building and a conventional building

It has been argued that “green” buildings have a better indoor environmental quality (as measured by the comfort perceptions of occupants) than conventional buildings and that this translates into a more satisfying workplace for the building's occupants and, in turn, a more productive workforce. To test this we measured the comfort and satisfaction perceptions of the occupants of a green university building and two conventional university buildings with a questionnaire that asked occupants to rate their workplace environment in terms of aesthetics, serenity, lighting, acoustics, ventilation, temperature, humidity, and overall satisfaction. The university buildings at the centre of the study are located in Albury-Wodonga, in inland southeast Australia. The green building, which is naturally ventilated, is constructed from rammed earth and recycled materials. The conventional buildings have heating, ventilating, and air-conditioning (HVAC) systems and are of brick veneer construction. We found no evidence to believe that green buildings are more comfortable. Indeed, the only difference between the buildings was that occupants of the green building were more likely to perceive their work environment as warm, and occupants who felt warm were more likely to describe their work environment as poor. However, the hydronic cooling system of this building was malfunctioning at the time of the study and hence this result cannot be generalised as a difference between green buildings and conventional HVAC buildings. All other aspects of comfort, including aesthetics, serenity, lighting, ventilation, acoustics, and humidity, were not perceived differently by the occupants of the two types of building.     

An evaluation model for indoor environmental quality (IEQ) acceptance in residential buildings

The indoor environmental quality (IEQ) in residential buildings is examined from the prospect of an occupant's acceptance in four aspects: thermal comfort, indoor air quality, noise level and illumination level. Based on the evaluations by 125 occupants living in 32 typical residential apartments in Hong Kong, this study proposes empirical expressions to approximate the overall IEQ acceptance with respect to four contributors, namely operative temperature, carbon dioxide concentration, equivalent noise level and illumination level, via a multivariate logistic regression model. A range of IEQ acceptances for regular residential conditions is determined and the dependence of the predicted overall IEQ acceptance on the variations of the contributors is discussed. The proposed overall IEQ acceptance can be used as a quantitative assessment criterion for similar residential environments where an occupant's evaluation is expected.     

Central automatic control or distributed occupant control for better indoor environment quality in the future

Based on a database accumulated from several recent surveys of office buildings located in a temperate climate (Denmark), the effect on occupant perceptions and symptom prevalence was compared in buildings with natural and with mechanical ventilation in which earlier studies have shown a discrepancy in the degree of perceived control. The database was composed of 1272 responses obtained in 24 buildings of which 15 had mechanical ventilation (997 responses) and nine had natural ventilation (275 responses). The number of occupant-reported control opportunities was higher in buildings with natural ventilation. Analysis of occupant responses, after grouping according to categories determined by the degree of satisfaction with the perceived control, showed that it was more likely the degree of control satisfaction that affected the prevalence of adverse perceptions and symptoms. Thus, the degree of control, as perceived by occupants, seemed more important for the prevalence of adverse symptoms and building-related symptoms than the ventilation mode per se. This result indicates that even though the development and application of new indoor environment sensors and HVAC control systems may allow for fully automated IEQ control, such systems should not compromise occupants’ perception of having some degree of control of their indoor environment.     

Relationship between quality of building maintenance management services for indoor environmental quality and occupant satisfaction

Two surveys were carried out to investigate the correlation between building maintenance management services for indoor environmental quality (IEQ) and occupant satisfaction. Each maintenance management organization manager was surveyed using the Evaluation Index of Maintenance Management Service Quality, created by Akira Takakusagi. Seven office buildings in Seoul, Korea were investigated in the first survey, and two buildings from the first survey were selected for analysis in the second survey. One is a building with good maintenance management services but low occupant satisfaction, and the other is an office building with low maintenance management services but high occupant satisfaction.     

Value creation for tenants in environmentally certified buildings

Previous research suggests that environmental certification (EC) affects rental rates in non-residential buildings, but there is still little understanding of how tenants differentiate such buildings from those without EC. This paper examines whether and how tenants perceive value creation in EC premises in Sweden. The findings (based on 29 questionnaire responses and 14 interviews with tenants in EC buildings) inform landlords and tenants on the development of EC strategies for improved organizational outcomes. EC creates value for tenants principally as support for their environmental management and reporting (e.g., low energy demand). EC is important for tenants internally, raising employee environmental awareness and improving employee attraction and retention. Tenants are generally positive about employee morale, indoor environmental quality (IEQ) and rental costs. However, it is not clear if such perceptions are dependent on features of modern premises in general, such as new fixtures, fittings and furnishings, and space-efficiency or from some EC-related feature. Tenants do not identify health or productivity increase in their EC premises. Findings suggest that the research focus should be shifted from investigating health and productivity increases through IEQ improvement to understanding the motivational improvement through value alignment with employees through EC.     

The power of qualitative data in post-occupancy evaluations of residential high-rise buildings

Using a mixed-method, case study research design, the present study explores four Toronto high-rise residential buildings in order to produce feedback about how occupants experience and behave in these buildings. The primary dataset is 700 comments received on 165 questionnaires. Content analysis was performed on the data, identifying envelope, heating, cooling and ventilation (HVAC), hot water, indoor environmental quality, and layout and design as the primary themes. The comments revealed important feedback for the designers and managers of these buildings; including important insights into the HVAC system, envelope, balcony, hot water delivery system, and noise control strategies. Though subjective in nature, the comments received from occupants are revelatory and have implications for the amount of energy consumed by the buildings, as well as the level of occupant satisfaction. Though not a substitute for quantitative problem solving, they are a complimentary strategy in the pursuit to improve the satisfaction and sustainability of the built environment.     

Investigation on the impacts of different genders and ages on satisfaction with thermal environments in office buildings

This paper investigates the effects of occupant gender and age on thermal satisfaction in office environments. The data used for the analyses was collected from 40-sampled occupants and their workstations on 38 floors in 20 office buildings in the U.S. with support from the U.S. General Services Administration. The field measurements include data collection for air temperature, radiant temperature, temperature stratification, relative humidity and air velocity of the sampled workstations. Occupant satisfaction surveys were distributed to each occupant in the workstations measured, and the thermal attributes of building systems were recorded. The objective and subjective data sets support statistical correlation analysis between environmental qualities and user satisfactions.     

Indoor air quality and occupant satisfaction in five mechanically and four naturally ventilated open-plan office buildings

Occupant responses and indoor environment characteristics were recorded and compared in five mechanically and four naturally ventilated open-plan office buildings by using a simple approach that enabled us to survey many buildings simultaneously. All occupant responses were obtained during one afternoon. In a pre-experiment, temperature and the concentration of CO₂ were monitored in 2–10 locations/office to evaluate the variation throughout the offices. A representative measurement point was subsequently selected and measurements of the same parameters were made during one week. All offices were monitored during the same week and occupant responses to the indoor environment were collected via the internet on the same day within that week. The temperature and the CO₂ concentration varied more and were in some cases higher in the naturally ventilated buildings, but occupant responses in terms of symptoms and adverse perceptions differed only modestly between the two building types. Although rarely supported by statistical significance, the results indicated a somewhat higher degree of satisfaction with the indoor environment and a lower prevalence/intensity of symptoms among the occupants in the naturally ventilated buildings.     

Thermal performance study and evaluation of comfort temperatures in vernacular buildings of North-East India

Solar passive techniques are being used in vernacular buildings throughout the world. Researchers have done extensive study on thermal performance of vernacular buildings in the different parts of the world. Vernacular architecture of North-Eastern India represents the principle of climate-responsive architecture, which still lacks experimental validation and quantitative analysis. Thermal comfort not only makes the occupants comfortable but also governs energy consumption in the building. Detailed field studies on thermal performances of typical traditional vernacular dwellings in different bioclimatic zones have been undertaken. This field study includes detailed survey of 150 vernacular dwellings, field tests and thermal sensation vote of 300 occupants on ASHRAE thermal sensation scale. Field test includes measurement of temperature, humidity, illumination level and building design parameters. Thermal performances of these vernacular dwellings were evaluated for winter, pre-summer, summer/monsoon and pre-winter months of the year 2008. This evaluation is based on ‘adaptive approach’, which is the outcome of the field studies and is now part of ASHRAE standard 55/2004 for predicting comfortable temperature of naturally ventilated buildings. This study also tried to find out the range of comfort temperature in these vernacular buildings for different season of the year. It has been found that these vernacular dwellings perform quite satisfactorily except in the winter months and the occupants feel comfortable in a wider range of temperature.     

A comparison of the occupant comfort in a conventional high-rise office block and a contemporary environmentally-concerned building

A comparative study of the occupant comfort (neutral) in a conventional high-rise office block and a contemporary environmentally-concerned building for Sheffield UK climate conditions was carried out. A questionnaire was designed for occupants to rate their workplace environment in terms of the thermal, visual, acoustic and overall perception and satisfaction level. The basic physical parameters were measured at the same time, e.g. air temperature, humidity, illuminance and sound level. It is inferred that (1) There is a noticeable difference between the conventional building and environmentally-concerned building in terms of their thermal and visual environment. (2) A clear distinction of the occupant sensation and satisfaction level towards their thermal and visual environment is presented between these two buildings. (3) The effect of basic physical variables on the occupants’ perception and satisfaction level becomes less significant when minimal standards are attained. (4) The acoustic satisfaction level however, was not perceived differently by the occupants of the two building types.     

Building‐related health symptoms and classroom indoor air quality: a survey of school teachers in New York State

Most previous research on indoor environments and health has studied school children or occupants in non‐school settings. This investigation assessed building‐related health symptoms and classroom characteristics via telephone survey of New York State school teachers. Participants were asked about 14 building‐related symptoms and 23 classroom characteristics potentially related to poor indoor air quality (IAQ). Poisson regression analysis was used to assess the relationship between these symptoms and each classroom characteristic, controlling for potential confounders. About 500 teachers completed the survey. The most frequently reported classroom characteristics included open shelving (70.7%), food eaten in class (65.5%), dust (59.1%), and carpeting (46.9%). The most commonly reported symptoms included sinus problems (16.8%), headache (15.0%), allergies/congestion (14.8%), and throat irritation (14.6%). Experiencing one or more symptoms was associated most strongly with reported dust (relative risk (RR) = 3.67; 95% confidence interval (CI): 2.62–5.13), dust reservoirs (RR = 2.13; 95% CI: 1.72–2.65), paint odors (RR = 1.73; 95% CI: 1.40–2.13), mold (RR = 1.71; 95% CI: 1.39–2.11), and moldy odors (RR = 1.65 95% CI: 1.30–2.10). Stronger associations were found with increasing numbers of reported IAQ‐related classroom characteristics. Similar results were found with having any building‐related allergic/respiratory symptom. This research adds to the body of evidence underscoring the importance to occupant health of school IAQ.     

Indoor environment quality and upgrading of European office buildings

Indoor environmental quality (IEQ) is an important quality aspect of office buildings, which is acknowledged in a new European methodology and software for office building refurbishment (TOBUS). In TOBUS, an inventory of complaints from occupants about IEQ is made as well as an inventory of characteristics of building and HVAC-system. Based on relations between characteristics of buildings and systems and the use of the building, different possible causes for the problems can be identified and possible actions for improvement can be selected. A relation scheme is provided with relations between objects and types, complaints of occupants in an office building, possible causes of those complaints and actions that should take away those complaints. Furthermore, a relation scheme is provided with causes and actions that cannot be related to an object. A procedure to qualify and quantify the IEQ performance of a building is given. This article describes the results of the field investigations in 12 European buildings focused on the IEQ part. Discussions and conclusions from this field study with respect to IEQ and with respect to the methods and procedures used are also presented.