Hot water – draining your summer energy bills

Hot summer days means lots of extra showers and loads of washing, making hot water the single biggest energy user in many homes in the warmer months. In fact EECA ENERGYWISE says most households spend more money on heating water than on space heating over a year.

However technical expert Christian Hoerning says there are easy ways to cut the waste and save hundreds of dollars a year.


High shower flow. Does your shower fill a 10 litre bucket in less than a minute at normal showering temperatures? An efficient shower head, with a flow rate of 9 litres a minute or less, could save you hundreds of dollars each year while still giving you a comfortable, effective shower. Even reducing the flow rate by 1 litre per minute could save a household of four more than $100 a year.

Long showers. The easiest way to cut hot water use is to linger a little less in the shower. In a family of four, each minute you add to your shower time is about $95 a year.  

Electric cylinder and pipes not wrapped. Prevent heat escaping by putting a wrap on your hot water cylinder and pipe insulation on any hot water pipes that are accessible (ask for these at your hardware store). For an older (pre-1987) cylinder and pipes, you could save up to $80 a year.

Dripping hot tap. This can waste up to 200 litres of water every day, or hundreds of dollars each year. Fixing a drip is usually as simple as replacing a washer.

Cylinder thermostat set too high. 60°C is optimum – that’s hot enough to prevent Legionella bacteria growing, but any hotter is a waste. Even an extra 10°C on the thermostat of your hot water system could be costing you $25 a year with a modern cylinder, or twice that with an older one.  Adjust your thermostat, or get an electrician or plumber to do it.

Half-full dishwasher loads. Minimise energy and water use by only running your dishwasher when it’s full. Check if your dishwasher has efficient settings like ‘eco’, ‘fast’ and ‘half load’.

Washing machine always on hot wash. Hot washes use more energy, so try switching to doing your laundry on a cold wash when practical. At four loads a week, you could save up to $80 a year.

For more advice to help you get the most from your hot water, check out the ENERGYWISE website.

Getting the most from your hot water - Energywise website

ENERGYWISE, brought to you by the Energy Efficiency and Conservation Authority, is the place to go for trusted information and assistance to help you make the best use of energy at home and on the road.

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Penny St John, Senior Communications Advisor, EECA

Phone: 027 687 3123