How does solar hot water work?

You may already know the benefits of solar hot water, but how exactly does it work?

Example of ground mount solar hot water system

  1. Roof-mounted thermal collectors harness the FREE heat energy from the sun
  2. Water from the tank is circulated through the roof-mounted collectors and is heated
  3. The heated water returns to the tank and is stored for later use
  4. At night or cold days an electric or gas booster assists in reaching the desired water temperature



Same Day Hot Water stocks three types of solar hot water systems, each with its own distinct method of keeping things steamy in your household.

Flat panel collector

Flat panel collectors are probably the most common solar hot water systems installed in Australia. They are reliable, low maintenance and effective.

Thick glass plates are fitted to the roof of your property. The glass, which is designed to withstand harsh weather conditions, houses a number of copper pipes which run from end to end. As the sun beams down on them, the copper pipes become extremely hot.

Cold water moves through these tubes, heating up along the way. Through a natural process, the hot water is then pushed into the fitted storage tank – in most cases without the need for a pump. Storage tanks are either fitted on the roof with the panels, or in the case of split systems, separately on the ground.

Once inside the water tank, the heated water remains insulated and hot until it travels through the water pipes into your property, ready for use.

Evacuated tube solar hot water

Evacuated tube systems use a number of glass tubes installed on the roof of your property. Inside the tubes are vacuums as well as copper pipes which stretch from one end to the other. As sunlight hits the dark absorber coating inside the tube, they become hot. This heat is transferred into an insulated storage area where water continually flows through and warms up.

The heated water is then pushed down into the storage tank where it remains until you’re ready to use it.

Lightweight, easy to install and low maintenance, evacuated tube solar collectors are impressively efficient and provide up to 90% of your hot water needs. With superior sun absorption capabilities, they are fast becoming the preferred solar hot water option amongst Australians.

Heat pump

Heat pumps are not as well known as their solar panel equivalents, despite heat pump technology being around for over 30 years.

Heat pumps work by absorbing heat from the air which surrounds it.

Air is sucked into the unit where it heats a liquid refrigerant and converts into gas as its temperature rises. The gas is compressed, generating heat, and is passed through copper tubes which are wrapped around the outside of the water tank. The heat is transferred to the water inside, making it rise in temperature considerably.

Though electricity is required as part of this process, it’s only about a third of the amount that is used by a normal electric hot water heater.


Solar hot water systems are built to maximise the unlimited power of sun; though there will be some days where your system will need a boost. On especially cloudy/cold days, a gas or electric booster is on hand to supplement your solar hot water heater.

This ensures that you never go without hot water. If you’ve also got solar PV panels installed on your property, an electric booster may be your preferred option. Without solar PV panels & natural gas connect, a gas powered booster is the more energy efficient choice.

Which system is best for me?

The best solar hot water system for you depends on a number of factors including, hot water consumption, property type, preferred running costs, budget and more.

For help making the best decision get in touch with Same Day Hot Water and our hot water specialists will happily answer your questions. Call 1300 88 13 43 to speak to a solar hot water professional.