Space heating is one of the largest energy uses in the average Australian household, accounting for 37% of the average appliance load, and 11% of the total energy load when cars are included. Heating requirements differ between warm and cold states, with space heating in Victoria accounting for 58% of the appliance load, and space heating in Queensland accounting for only 8% of the appliance load.
Households stand to gain significant energy use and cost benefits from the electrification of space heating. Current space heating is done primarily with a mix of natural gas, electric reverse cycle air conditioners (heat pumps), electric resistance heating, and wood fires. If we take each of these heating methods and look at how efficiently they heat a room, it becomes abundantly clear how we can save the most energy for Australian homes.
Natural gas heating has an efficiency of approximately 0.9. In other words, every 1 energy unit of natural gas is converted to 0.9 units of heat in a room. Electric resistance heating has an efficiency of approximately 0.95. Wood fires have an approximate efficiency of 0.75, converting 1 unit of energy in a log to 0.75 units of heat in a room.
By comparison, reverse-cycle air conditioners (heat pumps), have an approximate efficiency of a whopping 3.8 in the average Australian household. This means for every 1 unit of electricity, 3.8 units of heat in a room are created. Upgrading to an electrified home with heat pumps saves energy and money with no sacrifice in comfort.
On average, space cooling in Australia requires significantly less energy than space heating. This means Queensland and Northern Territory homes use significantly less energy on average. Our current methods of space cooling are relatively efficient, and are already practically all electric. For these reasons we can leave them as they are and will still get the cost benefits from cheaper solar electricity available in an electrified home. With rising average temperatures there will be a rise in air conditioning.