Elsevier

Building and Environment

Volume 75, May 2014, Pages 19-29
Building and Environment

Thermal comfort and occupant responses during summer in a low to middle income housing development in South Australia

https://doi.org/10.1016/j.buildenv.2014.01.013Get rights and content

Highlights

  • Occupant thermal comfort and responses during a summer period were investigated.

  • Occupants used passive means and adjusted their clothing accordingly.

  • Air-conditioning was the last preferred strategy due to cost implication.

  • Majority of ‘neutral’ votes fall within ASHRAE adaptive model acceptability limit.

  • Occupants' warm sensation occurred at temperature higher than standard assumption.

Abstract

This paper presents a study conducted to investigate occupants' thermal comfort and responses during a summer period in a low to middle income housing development. The study was conducted with the overall aims of understanding how occupants in this context responded to their indoor environment during hot weather and the strategies they used to achieve thermal comfort. The study found that resorting to air-conditioners was the least preferred strategy due to implications for their energy bills. Turning on ceiling fans, opening or closing windows and doors, and opening or closing curtains were the first set of actions taken by most occupants when they wanted to be cooler. The occupants also adjusted their clothing and activity according to the anticipated weather condition. The study highlights the importance of providing appropriate thermal comfort provisions, such as operable windows and ceiling fans, in houses in general, and particularly in low to middle income housing developments.

Introduction

It is predicted that Australia's climate will become hotter in the coming decades and that many locations will experience heatwaves of both higher temperatures and longer duration [1]. Recent extreme heat events in Australia have illustrated a range of problems associated with heatwaves from infrastructure failure, bushfires and economic loss through to increased morbidity and mortality [2], [3]. It is estimated that these problems will get worse in the future and that deaths due to heat could more than double in the next 40 years [4].

Increasing the access to air-conditioners is often perceived or promoted as the quickest way to respond to elevated temperatures. The World Health Organisation, however, advises that “climate-adapted building and energy-efficient design should be stressed over air-conditioning” [5,p.93]. This is quite realistic as there is increasing evidence that the people most vulnerable to heat – the elderly, isolated, chronically ill, socially disadvantaged – are often most likely to experience energy poverty1 [4], [6], [7].

Studies of heatwaves elsewhere have shown that most of the heat-related deaths occurred in the home or in nursing homes [8], [9]. Some aspects of building design such as lack of insulation and overheating in bedrooms were identified as possible causes of deaths during the 2003 heatwave in France [10]; however, there has been little research into house design and heatwaves.

In anticipating the impact of increasing temperatures on occupant thermal comfort and subsequent energy use in housing and realising the crucial role building design has on occupants' comfort, this study was conducted to investigate thermal comfort and responses of the occupants of a low to middle income housing development during hot weather. Specifically, the study aimed to find out: (1) whether the occupants were satisfied with their thermal environment during this period, (2) the actions that were taken if they were not satisfied with their thermal environment, and (3) at what point they would resort to using air-conditioners. The study was part of a research program, Framework of Adaptation of Australian Households to Heatwaves supported by the Australian Government's National Climate Change Adaptation Research Facility, where two of the main aims were to investigate occupants' thermal responses and adaptation to heatwaves and whether these would have a significant impact on energy consumption. The research involved monitoring 60 households located in Adelaide, Brisbane and Sydney and the results have been published by Saman et al. [11].

This paper focuses in more detail on the 10 dwellings from the Adelaide section of the research. These dwellings are occupied by low to middle income earners under an Affordable Homes program [16]. For this study, data collected about the householders' thermal preferences was supplemented by measurements of the dwellings' internal conditions and the external climate to explore the thermal adaptive strategies employed by the occupants. The results are compared to the adaptive comfort standard of ASHRAE 55-2010 [15] as the research project mentioned above [11] indicates that it is possible to apply the adaptive model, which will be briefly discussed below, in residential buildings.

Section snippets

Thermal comfort

The assumption that people will take action to be thermally comfortable, be it by relying on air-conditioning or by applying passive design strategies, underlies thermal comfort theory. This theory suggests that humans will have certain thermal sensations (hot to cold), that their thermal satisfaction lies within a certain range of conditions, and when exposed to a thermal environment outside this range they will feel thermally uncomfortable [15]. Fanger's Predicted Mean Vote (PMV) and

The study

The 10 households which are the focus of this paper live in two-storey apartments, built for low to middle income earners, in a housing development situated 8 km northeast of Adelaide CBD, South Australia (34.8° SL, 138.6° EL). Adelaide has a warm temperate climate, with cool wet winters and hot, dry summers. The hottest months are January and February, but the heat often continues into March. In recent years there have been some record-breaking heatwaves.2

Background questionnaire

Prior to conducting the thermal comfort survey, background information about the respondents was obtained through interviews using a standardised survey form. Information was collected about the occupants' age, gender, highest education level, occupation, and the total household income. During this initial interview, the respondents were also asked about how and when they operated their air-conditioner, as well as about their preferred steps for achieving thermal comfort.

Out of 10 households

Responses to the background questionnaire

Before the monitoring and the thermal comfort survey took place, the occupants were asked about how and when they operated their air-conditioner. They were also asked about the steps they took to achieve thermal comfort. The responses were as follows.

Although all apartment units are equipped with an air-conditioning system in the living room, the majority of the respondents stated in the interviews that they used it only occasionally. Instead, turning on the ceiling fans was the first method of

Discussions

The range of indoor temperatures during which actual ‘neutral’ votes occurred was found to mostly be within the 80% limits of the acceptable range of indoor temperatures. These, however, occurred when the occupants took some actions to be comfortable such as opening the windows or doors or turning on the fans. If these behavioural actions were not taken into account, then the range of temperature at which the occupants voted ‘neutral’ were still within the 80% acceptability limits but only

Conclusion

This paper has reported results from the study that aimed to find out: (1) whether the occupants of a low to middle income housing were satisfied with their thermal environment during a recent summer period, (2) the actions that were taken if they were not satisfied with their thermal environment, and (3) at what point the occupants would resort to using air-conditioners. The results can be summarised below.

Overall the ten dwellings seemed to provide a thermally comfortable indoor environment,

Acknowledgements

The authors wish to acknowledge the funding support from National Climate Change Adaptation Framework (NCCARF). The authors are also grateful for the cooperation from the residents of this housing development. Also acknowledged are the team leaders, Professor Wasim Saman and Dr Martin Belusko from University of South Australia, and Professor Richard de Dear from University of Sydney, as well as the assistance from Dr David Whaley of University of South Australia and Associate Professor Terry

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