Warm house, Cold house: a review of measures of thermal comfort used in Get Bill Smart's energy efficiency assessments

Managing thermal comfort, in both hot and cold climates, critically influences energy use in homes [1-4]. For low income households, who commonly live in thermally poor housing stock, maintaining thermal comfort can be costly relative to household income, leading to trade-offs between comfort, energy use and affordability. Comfort as a concept has been explored from many vantages, including as a physiological need [5,6]; a parameter for healthy housing [7]; as an energy efficiency building standard [4,8] and a cultural construct [9,10]. Yet, there is little research available that provides detailed insight into the relationship between thermal comfort and energy efficiency in existing housing stock or about the impact of support programs on these key indicators. This paper reviews measures of household thermal comfort as they relate to energy efficiency assessments in a project, Get Bill Smart (GBS), that worked with low income households in Tasmania, Australia. Thermal comfort and energy use data was collected over 15 months from 51 households, a sub-set of the 510 households participating overall. Longitudinal interviews and housing observations were also conducted. New thermal comfort and energy efficiency indicators were developed from this data. This paper demonstrates the application of these indicators by providing examples of findings in GBS. Suggestions are made for the refinement of measures discussed for use in future applications.