Saving money on hot water

Whatever hot water system you have, there are easy ways to reduce your energy bills. It isn't just about energy savings - if your water is metered, every litre you save is saving you money.

Easy hot water habits

  • Wash your clothes in cold water - a hot water wash can use 10 times more electricity than a cold wash. At four loads a week, this could save you around $60 - $80 each year.
  • Fill the sink - rather than leaving the hot water running when doing things like shaving.
  • Shower rather than bath - it typically uses only half as much water and energy.
  • Skip the hour long shower - in a household of three, each minute you add to your shower time is about $70 a year.
  • If you rinse dishes before loading the dishwasher, use cold water.
  • Run the dishwasher when it is fully loaded - and on an ‘eco' wash setting if available.

Switching off your hot water while away on holiday

Children playing on the beach in summer

Switching off your hot water cylinder while away on holiday can save you up to $8.00, if you are away for more than a fortnight.
If you choose to switch off your hot water cylinder, when you return home and switch it back on, wait at least half a day before using hot water - the water needs to get hot enough to kill any legionella bacteria first.

?Read more about checking hot water temperature

Manage your water use

Ease your shower flow

If your shower fills a 10 litre bucket in less than a minute, it's wasting water. Replacing your shower head for one with a more efficient flow rate of 9 litres a minute or less will cut your hot water use significantly. Or, you can install an inexpensive shower flow restrictor. Even reducing the flow rate by 1 litre per minute could save a household of three around $80 per year.

Watch: Check your shower and save on your energy bill | 5:27

You can compare the efficiency of new showerheads by reading the water efficiency labels in the shops - talk to a plumber about installing one.

Ease your tap flow

Flow control aerators for taps cost between $10 and $30 and can halve the volume of water you use while still giving good pressure. They’re great for taps over sinks or tubs that aren't regularly filled up, so the water flow volume is less important.

Fix dripping hot taps

Dripping hot taps could cost you hundreds of dollars a year (depending on how bad the leak is). Replace the washer or fitting - a new washer only costs a few dollars.

Choose efficient water products

Water efficiency labels appear on showers, taps, toilets, dishwashers and washing machines. Like energy rating labels, they use a star rating to show how water-efficient a product is compared to other products in the same class - the more stars, the more efficiently it uses water.

New Zealand Water Efficiency Labelling Scheme - Ministry for the Environment website

Keep in the heat

Wrap your hot water cylinder and hot water pipe

Pre-2002 electric hot water cylinders aren't insulated very well and should have a cylinder wrap. You should also insulate the first 1-1.5 m of hot water pipe coming off your hot water cylinder. Cylinder wraps cost around $60 and pipe insulation is about $5 a metre from hardware stores. For an older (pre-1987) cylinder and pipes, you could save about $80 a year. Note that you can't put a cylinder wrap on a gas hot water system.

Check your hot water temperature

It should be 60°C at the cylinder (to prevent the growth of legionella bacteria) and no more than 55°C at the tap so you don't get burnt (children are particularly vulnerable). Depending on your cylinder, you may need an electrician or plumber to adjust your thermostat. 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.

Maintain your hot water system regularly

This includes gently moving the easing lever of the temperature/pressure relief valve every six months, to prevent it from sticking. Glass-lined water cylinders should have their anode changed every 5 years, more frequently in hard water areas. A plumber can help if you're unsure. Depending on the type of system you have, you may need to do other forms of maintenance - check your manufacturer's instructions.

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