Comprehensive Energy Efficiency Upgrades to Existing Victorian Houses

Sustainability Victoria conducts trials to test the effectiveness of measures that can be taken by householders to modify – or retrofit – existing appliances or circumstances to improve the energy efficiencies in their homes.

A recent study was undertaken to analyse building shell (draught sealing and insulation) and heating system upgrades with the aim of improving thermal comfort during the winter months and significantly reducing heating energy consumption.

As well as reducing energy bills, improved thermal comfort during winter months is believed to provide health benefits for occupants, especially for vulnerable and low income households.

In the retrofit trial, 14 older homes (pre-2005) across Melbourne were retrofitted with a comprehensive package of energy upgrades valued between $12,000 – $13,000. The fourteen
houses that participated were quite inefficient, and had a gas consumption that was well above the Victorian average.

Where funds permitted, water heating, refrigeration and/or lighting upgrades were also undertaken at the houses, targeting other key areas of energy consumption. Metering equipment and householder surveys were used to assess the quantitative and qualitative impact of the upgrades, and to estimate the energy, energy bill and greenhouse gas emission savings achieved.

The project has confirmed that significant improvements to the thermal comfort of existing houses can be achieved in practice, as well as significant energy bill savings. It has also provided insights into how Victorians heat their houses, including the frequency of use, time of use during the day, and the inside temperatures achieved when the heating is operated.

While it was not possible to directly assess the health benefits arising from the retrofits, good quality data from overseas studies was used to estimate the potential medical cost savings. This suggests that if both the energy bill and health cost savings are taken into account, building shell and heating system upgrades are much more cost effective if viewed from a society-wide perspective.