Sustainability Victoria have published the results of their Comprehensive Retrofit Trial, which was undertaken in fourteen existing houses located in Melbourne.

The study investigated the impact of a comprehensive package of energy efficiency upgrades (or retrofits) applied to existing houses. The key focus of the study was on building shell (draught sealing and insulation) and heating system upgrades that could significantly reduce heating energy consumption, while also improving the winter comfort of the houses.

Research found that heating and water heating were the main areas of residential energy use, accounting for 97.2% of gas use and 52.6% of electricity use.

Key findings include:

• Heating energy consumption can be reduced by increasing the energy efficiency of a house’s building shell, and by upgrading the efficiency of the heating system
• Building shell upgrades increase thermal comfort in both winter and summer, and can reduce summer energy consumption if air conditioning is used for cooling. These retrofits can also reduce peak energy demand for heating in the morning and evening on cold winter days, and in the late afternoon on hot summer afternoons
• Federal policies and programs that improve the energy efficiency of building stock are key elements for reducing a county’s greenhouse gas emissions. The report noted the Australian Government’s Trajectory for Low Energy Existing Homes as an example of such national strategy.

More information here