Installing basic energy efficiency measures in homes not only boosts thermal comfort and reduces energy use, but improves quality of life and mental health while reining in healthcare costs, a study on the impact of energy-saving interventions has found. 

The Victorian Healthy Homes program is a multi-year study where a randomised controlled trial was used to measure the impact of an energy efficiency upgrade on temperature, energy use, health and quality of life, funded by Sustainability Victoria.

The program was carried out for The Australian Energy Foundation by two UTS research groups, the Institute for Sustainable Futures (ISF) and the Centre of Health Economics Research and Evaluation (CHERE). 

Just under 1000 households with low-income residents with an average age of 75 and an existing health condition from the western suburbs of Melbourne and the Goulburn Valley received energy efficiency upgrades, valued at $2800 on average. 

The upgrades were needs-based and included insulation, draught-sealing and reverse-cycle heating installation. 

The program was rolled out over three years between 2018 and 2020 and was compared to a control group that did not have the energy efficiency interventions. The final year of the program was impacted by Victoria’s strict COVID-19 lockdowns, with many households not receiving their upgrades until after winter had ended. 

The study found that average daily winter temperatures in households that received the interventions increased by 0.33°C, and up to 0.47°C in the mornings, when indoor temperatures tend to be lowest without the use of heating. 

This translated to a reduction of time spent exposed to cold indoor temperatures (defined as being less than 18°C) by 43 minutes per day. Households reported a reduction in electricity use of 0.9kWh/day, while gas use reduced by 7.1kWh/day, which translated into $69.70 in savings per household during the winter months.  

A range of health and comfort benefits 

Residents also reported feeling warmer and noticed less condensation, which leads to damp and mould. They also reported improved mental and physical health, including less breathlessness. 

Participants were also asked to rate their quality of life on three different scales, including the EQ-5D-5L and ASCOT measures and this subjective data was combined with objective health statistics including use of the Medicare Benefits Scheme, hospital admissions data and the Pharmaceutical Benefits Scheme. 

Energy bill savings equal even bigger health costs savings

Overall, participating households with energy interventions saved $887 per person on healthcare costs over the winter period. 

Combined with the energy saving and compared with the average $2800 install cost, the intervention would be cost-saving within three years (this analysis did not include development costs for the study). For every $1 participants saved in energy costs, they saved $10 in health. 

The research used innovative methodology 

UTS ISF program lead for healthy environments Kerryn Wilmot (pictured below) said the study was particularly rigorous because it used a methodology used in drug trials that had been applied to qualitative social research for the first time. 

“There’s an absolutely critical need for Australia to improve the quality of its existing homes,” Wilmot told a gathering at the study’s launch at the UTS campus in Sydney on Wednesday. 

UTS researcher Kerryn Wilmot

“Nearly half of Australian homes are estimated to have an energy rating of below 2 stars, compared with the 7 stars mandated for new homes. It’s crucial that we start overhauling substandard housing stock in Australia – especially for vulnerable members of the community,” she said.

Sustainability Victoria program lead Toby Cumming said the researchers were surprised at the magnitude of positive health impacts that flow from improved thermal comfort in homes. “If unheated, Victorian houses will be less than 18°C for 65 per cent of the year. Minor thermal upgrade can raise indoor temperatures while significantly reducing gas use and improve health and quality of life of householders.”

The researchers also found that poorly-rated homes reported the largest increases in thermal comfort as a result of the energy efficiency installations but did not lead to a “rebound” effect where participants increased their energy use, indicating that the program could contribute to significantly reduced energy poverty if rolled out more widely. The researchers said the methodology could also be applied to interventions to reduce extreme heat in indoor environments as a result of climate change. 

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  1. The temperature increases seem minuscule, is it possible the savings were placebo-esque?? People knew they’d had the interventions and so coped differently with the cold?

    1. The study found that people who’d had the interventions used their gas heating less, and that this was because they felt warm enough. The temperature increases were small, but just enough so that people didn’t feel they had to run their appliances 24/7, which was what a lot of people were doing before the intervention. This is quite an important change in behaviour, and one that has clearly saved money and CO2 emissions.