Solar hot water - how it works

If you have a question about solar hot water not covered below, try our FAQ or please feel free to contact our friendly team - they'll be glad to assist you! Don't forget to check out our great range of solar hot water systems, specials and solar hot water rebate information; or you can complete a brief form for a free, no-obligation solar hot water quote!

How solar hot water works

Aside from cost and greenhouse gas emissions savings, the beauty of a solar hot water system is its relative simplicity and durability!

There are two types of collectors used in a solar hot water service:

• flat plate collectors (suitable where tank roof mounting is required)
• evacuated tubes (more efficient and great for frost prone areas)

Flat plate solar collectors

Flat plate collectors work on copper pipes running through a glass covered collector, often connected to a water storage tank on the roof. The hot water can then thermo-siphon itself in and out of the tank, thus heating the water. View our range of flat plate collector systems

Evacuated tube solar collectors

Evacuated tubes use a glass tube with a vacuum inside and copper pipes running through the centre. The copper pipes are all connected to a common manifold which is then connected to a slow flow circulation pump that pumps water to a storage tank below, thus heating the hot water during the day. The hot water can be used at night or the next day due to the insulation of the tank.

The evacuation tube systems are superior as they can extract the heat out of the air on a humid day and don't need direct sunlight. Due to the vacuum inside the glass tube, the total efficiency in all areas is higher and there's better performance when the sun is not at an optimum angle - such as when it's early in the morning or in the late afternoon. View our range of evacuated tube systems.

Evacuated tube vs. flat panel - which is more efficient?

The short answer is evacuated tube - it's not only more efficient, but also more durable and cheaper to repair should there be accidental damage - learn more about evacuated tube vs. flat plate collectors.

The water tank and thermal mixing

As heat rises, the hot water delivered to the tank from the solar collector is drawn from the top for use in the house

As the temperature of the water may exceed 60 degrees Celsius (a requirement to kill bacteria), in order to ensure a safe temperature at the taps, a tempering valve will reduce the temperature to around 45 degrees Celsius.. 

Electricity and gas boosters

While the sun can provide sufficient energy to provide you with plenty of hot water for most of the year, there may be extended periods of cloudy, cold days where your system will need a helping hand. This is provided with an electricity boosted or gas booster system. 

Boosting using a tankless gas water heater is the most efficient boosting method as boosting only occurs when hot water is used. With an electric system, the tank is heated as soon as the internal temperature drops.

Retrofitting for solar hot water

If your current hot water system has plenty of serviceable life left or you've recently purchases a gas/electric hot water system, you can still go solar with  a retrofit kit!

Hot water and household energy usage

Electric and gas hot water systems account for approximately 20% of a household's greenhouse gas emissions. Aside from Energy Matters' discounted prices on solar hot water equipment and generous government rebates, by installing a solar water system you will reduce these emissions and also save up to 75% of your water heating costs! the table below is sourced from the Department of Environment and Climate Change NSW.

A gas-boosted solar water heater will be the most environmentally friendly option as shown below.

Annual solar hot water savings

In the table below, you can gain an estimate of how much you can save each year by switching to a hot water system

To gauge where you would fall in the table.

• Light users will have 4 minute showers and wash clothes with cold water. Most households in Australia will be classified as heavy. 

• You can use the heavy classification to adjust for temporary residents as well. 

• Check your bill if you're not sure whether you use peak or off-peak electricity.

• If your gas heater was installed prior to 2002, choose the ‘older gas heater’ option.

• If you use a gas heater rated 2 Star or less, choose the older option.

• If you use a gas heater rated 3 Stars or more, choose the new gas heater option.

These savings, in addition to solar hot water rebates, make solar hot water not only the right environmental move, but also financially rewarding one in most circumstances!

Get started on your environmentally friendly and cost-saving solar hot water system! Contact our team of friendly experts for free, no-obligation advice, try our solar hot water quoting system or buy solar hot water systems in our online store now! Don't forget to check out any applicable rebates and our specials. We can also arrange for installation of your system just about anywhere in Australia!