Choosing a water heating system

How much hot water your household uses, and the electricity and gas prices in your area, determine if it is worth paying more upfront for a highly efficient water heating system, or whether a conventional electric or gas system is sufficient. Choosing a highly efficient system that uses renewable energy, such as the sun’s heat or electricity (which is about 80% renewable on average) also reduces the environmental impact of your hot water use.

What to think about

When you’re looking at buying a new hot water system, consider the following:

How much hot water do you use?

  • How many showers and baths does your household have every day?
  • How many people live in your house now, and how many might there be in the future?
  • Does your dishwasher or washing machine draw on the hot water system?

How much are you paying now?

  • Look at your bills over the last 12 months. Your hot water may be detailed separately on your bill.
  • If you have an electric hot water cylinder your hot water energy use may be detailed as “controlled electricity”.
  • If you have gas water heating, then your gas bills will tell you – if you use gas for space heating too, then look at some summer gas bills when you did not use any space heating.
  • If in doubt, contact your energy supplier for help with calculating the cost.

Environmental considerations

  • Choosing a highly efficient system that uses renewable energy, such as the sun’s heat, wood (through a wetback) or electricity (which is about 80% renewable on average) helps reduce the environmental impact of your hot water use.
  • Gas water heating causes more greenhouse gas emissions that contribute to climate change than other water heater types that use renewable fuels or electricity.

Compare upfront and running costs of different water heating options

  • Use our water heating systems tool to compare the upfront and ongoing costs of different water heating options for your situation.

 Water heating systems tool

More information about different water heating systems

 Types of water heating systems

Other considerations

System sizing

  • Whether you choose a system with a storage tank (cylinder) or a continuous flow system, talk to your supplier about correct sizing of your system according to the hot water needs of your household.

When you design a new home or change the layout of an existing one

  • Aim to group areas requiring hot water close together - bathroom, kitchen, toilets and laundry. As well as reducing the initial plumbing costs, you’ll save on energy expenses. There will be less hot water wasted sitting in longer pipes, and less time for the hot water to get to its end use.