Outcomes from the Victorian Healthy Homes Program: a randomised control trial of home energy upgrades

Introduction The Victorian Healthy Homes Program (VHHP) is the first randomised control trial (RCT) in Australia that investigates the impact of thermal home upgrades on energy and health outcomes in vulnerable individuals over winter in Victoria Australia. Methods A staggered parallel-group RCT design of 984 vulnerable households. The intervention group received their upgrade prior to their winter of recruitment and the control group received their upgrade after the winter of their recruitment. Results A relatively low-cost and simple home upgrade (average cost AU$2,809) resulted in reduced gas consumption (−25.5 MJ/day) and increased indoor winter temperatures (average daily increase of 0.33°C), and a reduction of exposure to cold conditions (<18°C) by an average of 0.71 hours (43 minutes) per day. The intervention group experienced improved mental health as measured by the SF-36 mental component summary and social care related quality of life measured by adult social care outcomes toolkit (ASCOT), and lower healthcare costs overall (an average of AU$887 per person) over the winter period. Conclusions The home upgrades significantly increased average winter indoor temperature, improved mental health and social care-related quality of life, and made householders more comfortable while bringing about reductions in overall healthcare use and costs. STRENGTHS AND LIMITATIONS OF THIS STUDY First randomised control trial of its kind in Australia to study the impact of thermal home upgrades on energy and health outcomes. The use of RCTs for such interventions is uncommon but provides a powerful approach to evaluation that can minimise the effects of confounding. The program was specifically designed to target vulnerable populations. These are groups with the most potential to benefit from home upgrades, either because of their socio-economic status or because of their chronic health conditions, or both. The retrofitted upgrade was tailored to each home based on need and delivered for a modest budget (up to AU$3,500) COVID-19 impacted the power of the study because not all upgrades were able to be delivered prior to winter. This was particularly relevant for the secondary health outcome measures.