Electricity costs
The cost of operating an electric-boosted solar or heat pump hot water system depends on the electricity tariff you are charged. Electricity tariffs differ between continuous and off-peak supply, and vary across the States and Territories.
Continuous electricity supply:
- provides power so that your water can be heated at any time of the day or night
- is charged at a single price and has a higher price per kilowatt hour (kWh) than off-peak electricity
- should be used for circulation pumps in solar hot water systems to ensure the pump can operate when needed e.g. for frost protection
- is important for heat pump systems as they need to be powered during the day to gain energy from warmer daytime air to be most efficient, especially in cooler regions
- electric boosters connected to continuous supply could turn on at any time of the day, which increases reliability, but may result in higher electricity bills
- may be required for gas boosted hot water systems.
Off-peak electricity supply:
- generally only provides power for your water heater for between 6-12 hours a night - check with your local electricity retailer for details of off-peak hours
- is only available for properties with a hard-wired dedicated water heating circuit
- has a significantly lower cost per kilowatt hour (kWh)
- does not supply electricity for part of the day, so if you have a solar hot water system your supply of hot water may be insufficient during periods of high hot water use and/or cold, cloudy weather
- is not suitable for solar systems with a gas booster as electricity is needed at all times to enable ignition of the burner
- is not suitable for solar systems with a circulation pump as the system must be able to circulate water at any time
- is not suitable for heat pumps in cold or frost-prone areas since they must be able to operate during the day when off-peak electricity is generally not available.
To learn more about your electricity tariffs, contact your electricity provider.