Electric water heating
Electrical water heating comes in two main types - electric hot water cylinders, and continuous flow electric systems.
Electrical hot water cylinders
Electrical hot water cylinders heats the water with an electric element in an insulated tank to a temperature set by a thermostat. It is the most common form of water heating in New Zealand.
What's good about them
- The upfront cost is relatively cheap.
- You can buy cylinders with additional connections suitable for having a solar panel, heat pump water heater or wetback added in future.
What to be aware of
- The running costs are relatively expensive compared to other water heating options (unless a cheaper night-rate tariff is used).
Switch to a night-rate electricity tariff if you can
Switching to a night rate electricity tariff could halve your hot water bill. It's not available everywhere - check with your electricity supplier first.
Before switching to night-rate, test that your cylinder is big enough to store a day's water. Switch it off first thing in the morning and back on before you go to bed for a couple of days to see if you run out of hot water. If you have enough hot water to see you through, organise a night rate tariff with your electricity supplier.
If your cylinder feels warm to touch, put a wrap on it.
Newer electric hot water cylinders, installed after 2002, will be A-grade and well insulated, but older cylinders are likely to be inadequately insulated. A cylinder wrap will hold the heat in - wraps cost around $60 - and you can still use the hot water cupboard to air clothes and linen. Insulating your hot water pipes will also help prevent heat loss - pipe insulation costs around $5 a metre. For an older (pre-1987) cylinder and pipes you could save up to $80 a year.
Continuous flow electric systems
Continuous flow electric systems heat water as it runs through.
What's good about them
- They can work well as a secondary water heating system. For example, if you have a kitchen sink that's a long way from your main water heater, a continuous flow system located under the sink can provide hot water instantly. This reduces water use and the energy lost from the hot water left in the pipe.
What to be aware of
- Flow rates can be limited by the capacity of your home's wiring - check with your supplier.
- They cannot be used on cheaper controlled and night-rate electricity tariffs so are usually more expensive than electric hot water cylinders.
- If they are used often during peak times, they place an additional burden on the electricity supply network.
- Though the hot water never runs out, using more than you need to is a waste of money, energy and water.
- Larger units are available that can heat the water for the whole house but these generally require three-phase electrical supply, generally associated with industrial or commercial sites. This type of electrical supply costs extra to install in the home and usually more per unit than standard residential rates.
Heat pump water heating
Heat pump water heaters use the same technology as heat pumps used for home heating. They use electricity efficiently to heat hot water by harnessing energy from the outdoor air or ground.
- Find out more about heat pump water heating.
More information
Choose the right water heating system
Simple ways to save on hot water
