The Victorian Healthy Homes Program was a randomised controlled trial designed to measure the impact of an energy efficiency and thermal comfort home upgrade on temperature, energy use, health and quality of life. 

Analysis indicated that a relatively minor upgrade (average $2,809) had wide-ranging benefits over the winter period. Subjective experience of warmth is important; it does not always match temperature measurements. Householders in the intervention group were more than twice as likely as controls to report that their home felt warmer over winter. 

These gains in thermal comfort were obtained despite a significant reduction in gas use in upgraded homes, and no change in electricity use. There was no evidence of a rebound effect, with intervention participants less likely than controls to use their main heater and less likely to resort to other options to stay warm. 

Importantly, the upgrade was associated with benefits in health, with reduced breathlessness and improved quality of life, particularly its mental health and social care aspects. Health benefits of the upgrade were reflected in cost savings, with $887 per person saved in the healthcare system over the winter period. 

Cost-benefit analysis indicated that the upgrade would be cost saving within 3 years – and would yield a net saving of $4,783 over 10 years – due to savings in both energy and health. Savings were heavily weighted towards healthcare: for every $1 saved in energy, more than $10 is saved in health.