Based on heating a house for an average of five months a year at 6 hours per day, the data suggests that heating a house of up to about 170m2 via gas-fired hydronic radiators is the cheapest, most efficient form of home heating. Gas fired hydronics was shown to cost around $915 per year, with the next best method being gas fired – ducted heating at $970.
The Sustainability Victoria report data compares the most common forms of gas and electric home heating and itemises the annual costs for each. It also enables comparison between heating a whole house or just one room. The Sustainability Victoria site contains a wealth of other information resources for home heating efficiency.