The table below provides approximate annual running costs for a range of types and sizes of different heating options.
|Room size||Heater types||Energy star rating||Annual energy cost||Annual GHG emissions (kg/yr)|
|Room / Space heating|
|Small room 12m2||Gas heater||$170||345|
|Portable electric heater||N/A||$385||1410|
|Reverse-cycle air conditioner||$140||510|
|Medium room 30m2
|Electric panel, convection or fan heater||N/A||$935||3460|
|Reverse-cycle air conditioner||$310||1140|
|Large area 60m2||Gas heater||$730||1685|
|Electric panel, convection or fan heater||N/A||$1860||6825|
|Reverse-cycle split system air conditioner (8kW)||$640||2365|
|Small house 100m2||Gas ducted heating||Not zoned||$1130||2825|
|Gas hydronic||Not zoned||Standard||$1035||2520|
|Ducted reverse-cycle air conditioner||Not zoned||$975||3600|
|Medium house 160m2||Gas ducted heating||Not zoned||$1705||4520|
|Gas hydronic||Not zoned||Standard||$1555||4030|
|Ducted reverse-cycle air conditioner
|Large house 220m2||Gas ducted heating||Not zoned||$2265||6215|
|Gas hydronic||Not zoned||Standard||$2060||5545|
|Ducted reverse-cycle air conditioner||Not zoned||$2030||7500|
* Approximate costs per year, based an average existing (pre-2005) 2 Star house in a Melbourne climate, heating to 20°C all day on the weekend (7am to 10pm) and in the morning (6am to 9am) and evening (5pm to 11pm) on weekdays, as needed.
Based on an electricity tariff of 31.9c/kWh. Gas tariffs are based on a declining block structure, which means the unit cost of gas decreases as gas use (or area being heated) increases. Gas tariffs used for room heating: 12m2 – 2.75c/MJ; 30m2 – 2.64c/MJ; 60m2 – 2.45c/MJ.
Gas tariffs used for central heating: 100m2 – 2.32c/MJ; 160m2 – 2.17c/MJ; 220m2 – 2.09c/MJ. The energy tariffs do not include any pay on time discount, or any fixed supply charge.
The figures for "zoned" operation assume that heating in the bedroom areas is switched off during the day (9am to 5pm) on the weekends. The zoning does not affect the operation of the heating on weekdays, as the house is not occupied during this time and the heating is assumed to be off. Other zoning arrangements are possible, and would change the saving achieved by zoning.
Actual costs for your house will depend on the area heated, how long you run the heating for, your thermostat settings, how well insulated the house is, your energy tariffs and your local climate.
To estimate the running cost for a cold climate (e.g. Ballarat) multiply these figures by 1.3, and for a warm climate (e.g. Mildura) multiply these figures by 0.7.
To estimate the running cost for a 5 Star house in a Melbourne climate multiply these figures by 0.4, and for a 6 Star house multiply these figures by 0.3.