If you’re in hot water over your latest power bill, remember water heating accounts for about 30 percent of household energy usage. A few tweaks to your hot water system and usage can result in big savings.

First, check your hot water system’s insulation. Cylinders and pipes installed before about 2002 generally aren’t well insulated – you can buy cylinder wraps from hardware stores for about $60 and pipe insulation for $5 per metre (ask for “thermal pipe lagging”). New cylinders lose less heat with extra insulation, but could still benefit from an insulating wrap.

You can also save money by running your hot water cylinder only at night, but you’ll need to be on one of the following electricity plans:

  • Controlled, where you have separately wired appliances (normally the hot water cylinder) that the electricity company can switch off for a few hours each day during peak times in return for a lower electricity price.
  • Time-of-use, where the amount you pay for all electricity changes depending on the time you use it, with lower night and off-peak tariffs.

Installing an efficient showerhead can save you up to $500 per year. The rule of thumb is your shower is wasting water if it fills a 10L bucket in less than a minute. Replace your inefficient showerhead with one with a flow rate of less than 9L per minute. We tested low-flow showerheads and found a few that saved water while still giving a good combination of comfort and effectiveness.

Some people think only using one hot water cylinder element can save power. A hot water cylinder usually maintains its water temperature at about 60°C, so whether you’re using one element or two, the cylinder has to do the same amount of work to heat the water.

In fact, switching both elements on may be more efficient as it promotes even heating of the water through convection (the circulation of water due to hot water having a lower density and rising to the top).

Report by George Block.

More information

See Water heating options for more about water heating costs and savings.