At home

Solar energy

Why waste your money on ever-increasing electricity and gas bills when you could use the sun’s energy to heat your water?

Enough sunlight falls on Australia to supply the nation’s total energy needs many times over. Solar modules (or panels), usually on your roof, can convert the rays to electricity.

The modules should be placed facing north and tilted upwards. Your installer can advise you on the best exact orientation and inclination for your location. Some types are fabricated to look like building materials – roof tiles, wall materials, and semi-transparent windows for atriums and skylights – so they blend in.

Apart from modules, a solar hot water system consists of a water storage tank, and a gas or electric booster. With the installation costs these systems are a significant purchase, but the longer term savings are huge, with your electricity or gas bills for heating water being slashed by 65 to 80 per cent.

Don’t wait for your old boiler to fail – plan for your solar hot-water system now, with this guide to requirements:

Solar hot-water system requirements

Number of people in household: 1–2

Hot water system capacity required (litres): 160 - 250

Solar collector size (m2): 2

Number of people in household: 3–4

Hot water system capacity required (litres): 300 - 370

Solar collector size (m2): 4

Number of people in household: 5–6

Hot water system capacity required (litres): 400+

Solar collector size (m2): 6

Running costs

The cost of heating water with solar energy, compared with systems using mains electricity, natural gas and liquefied petroleum gas (LPG).

Solar hot water system

Annual cost *

Electric (peak)


Electric (off-peak 1)


Natural gas




Solar, with mains electricity boost (peak)


Solar, with mains electricity boost (off-peak 1)


Solar, with natural gas boost


Solar, with LPG boost


Electric heat pump (peak rate)


* Approximate cost per annum, based on hot water usage three to five person household of 156 litres of per day. Costs may vary depending upon usage patterns, efficiency of system, climate conditions and tariff rates. Electricity (domestic controlled load 1 and 2) and natural gas tariffs are based on AGL price list. LPG tariff is based on indicated rate from Origin Energy. Prices as at August 2013.

Important considerations

  • Use an accredited installer and ensure all plumbing is carried out by a plumber who is licenced to issue a certificate of compliance.
  • Install your system as close as possible to the kitchen, bathrooms and/or laundry to minimise heat loss.
  • If a roof tank is to be installed, the installer must assess the roof’s structural strength and compliance with any regulations.
  • Have the storage tank and solar modules as close together as possible, to reduce the length of the connecting pipes.
  • Insulate the pipes, in accordance with manufacturer’s guidelines.
  • Fit a low-flow showerhead. Showering accounts for more than 30 per cent of household hot water.
  • Keep the booster thermostat at its recommended setting of 60°C.
  • Turn off the booster when back up is not required, or fit appropriate timers.
  • If you live in an area prone to frost, make sure your system and accessories are suitably warranted.

For more information on solar water heating, see the Australian Government’s Your Home website and Hot water.

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Page last updated: 27 February 2015