Calculators
Gas, or reverse-cycle and a heat-pump water heater?
Compare a year on gas heating and gas hot water with a year on reverse-cycle air conditioning and a heat-pump hot water system. Enter your heat demand, prices and the cost of the new equipment. The default heat demand suits a cold-climate house; most Australian homes need far less, so work it out from your gas bills.
Common questions
What efficiency figure should I use?
Reverse-cycle air conditioners and heat-pump water heaters deliver several units of heat for each unit of electricity. Use the figure on the product's energy rating label or in the installer's quote; cold nights in Canberra or the Tablelands lower it.
Which electricity price should I enter?
The usage rate from your plan, including GST. If your water heater runs on a controlled load or you can run things during the day on solar, your real cost for that share is lower.
Is going electric worth it?
It depends on your gas and electricity rates, the age of your gas appliances and whether rooftop solar can run them in the day. It usually looks best when a gas heater or water heater is due for replacement anyway, because you avoid buying a new gas appliance and may be able to drop the gas supply charge.
Are there rebates?
Heat-pump water heaters can earn small-scale technology certificates under the federal scheme, which installers take off the price, and some states add their own rebates. Amounts change, so check your state energy website and ask for the discount as a separate line on the quote.