BOLT-ON Heat Pump

Siddons BOLT-ON – The easiest and most cost effective way to make solar savings!

The BOLT-ON is a new and brilliantly designed heat pump that works with any storage tank, new or existing, night or day.

Why pay for a new storage tank if your current tank still has life in it, even though its heater may not work or is too expensive to run?

Siddons introduced the heat pump to Australia more than 30 years ago and has been improving this efficient solar technology ever since. It takes solar heat from the air rather than direct radiation from the sun, so it can work in all weather conditions, from minus 5°C to 45°C, night or day. And it doesn’t take up your roof space; you can use that for PV electricity-generating panels instead.


And because the BOLT-ON is energy-efficient, it’s much cheaper to operate than electric element or gas bottle water heaters. For a family of two adults and two kids, you can save up to 75% of your hot water costs or around $600 per year, savings that will increase as the cost of electricity and gas increases.

According to not-for-profit think-tank Beyond Zero Emissions, replacing an electric element water heater with a Siddons BOLT-ON reduces your CO2 emission by around 3 tonnes per year (based on rebate Zone 4). Replacing two electric element water heaters with BOLT-ONs has the same impact on the environment as taking a car off the road.

The BOLT-ON does not need an electric element, gas burner or condenser coil from the storage tank to help it heat, so you can buy it on its own and bolt it onto your existing storage tank.


  • Upgrading your existing electric element or gas bottle water heater to solar heat pump and save around $600 per year
  • Attaching the BOLT-ON to your existing water heater that may no longer be working to avoid having to pay for a new storage tank
  • Including the BOLT-ON with a new hot water storage tank, which will earn you rebates to help cover the extra cost

It is also much smaller in size than a typical integrated unit and therefore much easy to transport. It will even fit in the back of a ute or a station wagon.

Upgrading your existing electric element or gas bottle water heater to solar heat pump and save around $600 per year

The BOLT-ON was designed for easy installation. Any plumber can do it. And the BOLT-ON is just as easy to uninstall. This means that if you rent you can even take it with you when you move!

The BOLT-ON has a sophisticated digital controller that enables you to choose the time of day the unit runs, making it easy for you to take advantage of cheaper off-peak rates, or run it in the afternoon at the warmest time of the day. You can also set your preferred water temperature.

The BOLT-ON’s digital controller and pressure gauge (previously only found on commercial heat pumps) together make it easy to monitor the performance of the BOLT-ON. The controller will display the water temperature in your tank and the temperature of the air,  and will continually check performance against a number of factory set parameters, and let you know if service is required, just like a modern car.


 Key details of the BOLT-ON warranty are as follows:

BO warranty


For full details of the BOLT-ON warranty, click here.

The BOLT-ON is backed by Siddons national service desk: call 1300 SID SOL

Siddons BOLT-ON. Solar savings made easy!



Siddons offer a range of third-party water storage tanks that you can connect to your Siddons BOLT-ON. To read more, click here.


This kit is designed to facilitate installation of your Siddons BOLT-ON and storage tank. To read more, click here.


For areas with poor quality water, this water softening kit will provide many benefits, including prolonging the life of your Siddons BOLT-ON and storage tank. To read more, click here.


Rain water is inherently acidic with pH of around 6.0. The Clarence pH boost filter is designed for rain water tanks to lift the pH to above 6.5. The ideal pH for water is between 6.5 and 8.5. This will not only be best for your hot water storage tank but for all your tapware and appliances that come into contact with hot water as well.

* Note that pH of between 6.5 and 8.5 is a warranty condition. To read more, click here.


Designed for fitting existing electric element storage tanks. To read more, click here.



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