Residential energy efficiency and health – a mixed methods study of a quasi-randomised controlled trial of energy efficiency improvements of the homes of low-income Home and Community Care recipients near Melbourne, Australia

摘要

At the intersection of climate change mitigation as an opportunity for health and housing as a social determinant of health, this research contributes to a better understanding of residential energy efficiency and health as a socio‐technical system. Improvements in residential energy efficiency may benefit health via the pathways of more adequate indoor temperatures, reduction of energy costs and improved satisfaction with the home, yet better knowledge about the contextual mechanisms is needed for the development of effective intervention strategies. Two observational studies of over 100 homes with an average 4.7 AccuRate stars in Melbourne, Australia, suggested that the current home energy efficiency star rating was a poor predictor of winter warmth or summer cool, and that householder heating and cooling practices had a strong influence on indoor temperatures. The main study of this PhD research was a mixed methods evaluation of a quasi-randomised controlled trial of energy efficiency retrofits of the homes of low-income Home and Community Care recipients near Melbourne. The final sample comprised 13 control and 16 intervention homes with a pre-intervention mean of 2.9 and 2.7 FirstRate stars respectively. Draught proofing and roof insulation raised the star rating of the intervention home to 3.5 stars. The study combined a phenomenological enquiry into householder practices with quantitative analyses to explain the outcomes for winter. The study found statistically significant benefits in electricity costs, householder confidence in heating and the householders’ perceived sense of control. The intervention also appeared to have benefited indoor warmth, heating energy costs, greenhouse gas emissions, comfort and psycho-social benefits of the home, with weak benefits in health. Although underheating appeared to have been reduced, it remained a common problem due to the switching off of heating overnight, open bedroom windows, limited recognition of heating as a preventative measure and voluntary underheating. The perceived affordability of energy was shaped by the nature of the energy contract, the budget available for energy and the payment mode. As heating was part of caring, acute illnesses led to more heating and more warmth, and the departure of cold-sensitive persons to the reverse outcomes. The weak effects on health outcomes were explained by non-dwelling related factors that affected the householders’ physiological, mental and social health. What mattered most to the participants were the retrofit measures, the gains in comfort, the expected benefits in costs as well as educational and social benefits, as many householders had limited energy literacy and were socially isolated. The findings of the study provided new insights for the design of residential energy efficiency improvement programs for older or frail Australians that could provide co-benefits for health and equitable climate change mitigation outcomes. However, larger studies are needed to confirm these findings and to explore outcomes for summer. Considering that balancing the demands of health and climate change mitigation is a complex undertaking that relies on the efforts of individuals, households, communities, researchers, regulators, building and health professionals, a common conceptualisation of energy, indoor temperatures, housing quality and health is required followed by collective action.