BOLT-ON Solar Heat Pump (no tank)

BOLT-ON Solar Heat Pump (no tank)


The BOLT-ON provides an easy and affordable way to go solar: meeting all your hot water requirements, minimising your carbon pollution, and saving up to 72% of your hot water heating costs. That’s around $600 per year for the average family home!

The BOLT-ON is a highly efficient, stand-alone solar hot water system, designed to produce all the hot water required in residential and small-medium commercial settings. It uses heat pump technology – the same technology that is used in your refrigerator (but in reverse) – to heat water. It does not use direct sunlight but uses the ambient heat in the air. As a result, it can heat water at all times – even at night and on cloudy days. As the sun heats the ambient air, heat pumps are considered a solar technology.

The BOLT-ON needs to be paired with a hot water storage tank to store the hot water it produces. It can easily be retrofitted to existing tanks and is portable. Therefore it is a great option for renters too. If you require a package with a BOLT-ON and new hot water storage tank, please click for our 250L or 315L tank packages.

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Advantages of going solar with the BOLT-ON:

  • The BOLT-ON Heat Pump will heat your water faster and use less energy than electrical element heaters – you will have more hot water, save money and reduce carbon emissions.
  • Heat Pump technology is reliable, having been around for decades. It is the same technology that is used in refrigerators. To back this, we provide you with a 5-year warranty on the BOLT-ON.
  • Customer service – as a non-profit worker owned cooperative we are motivated only with benefitting our members. When you purchase an Earthworker hot water system you become a member of Earthworker Cooperative. Our priority is giving you as much support as possible.
  • Huge energy, cost and carbon savings –
    • Heat pump technology allows you to use 1kW/h of electricity to produce 3.6 kW/h of heat, at 20°C air temperature. And the efficiency rises by more than 20% per 10°C rise in air temperature.
  • You save up to 72% of your hot water heating costs* – that’s an annual saving of around $600 for the average family home or $3,000 for the warrantied life of the BOLT-ON. *Compared to electric element or gas bottle water heaters.
    • Reduce your hot water carbon emissions by up to 75% or eliminate them completely by switching your electricity to GreenPower or pairing the BOLT-ON with solar PV.
  • You are supporting ongoing Australian jobs in local, worker owned cooperatives that manufacture renewable energy technology. You are also supporting our ongoing mission to expand worker owned cooperatives into other industrial areas of Australia.
  • You can retrofit the BOLT-ON to your existing hot water storage tanks – no need to chuck out your current tank. You can also upgrade to our top-rated ‘Solar Ready’ tank (qualifies for significant government rebates). Click for our 250L or 315L tank packages.
  • Very low maintenance. Just like a refrigerator, the BOLT-ON has very low maintenance requirements – simply brush any dust off the air inlet vents periodically.
  • You can apply for a special fixed low interest finance deal from bankmecu. This allows you to pay off the BOLT-ON over 5 years with their flexible repayment options.
  • No roof-top solar panels required – you do not need direct sunlight, so your system can be placed in the shade and can heat water day and night in any temperature between -5°C and 45°C.
  • Can be easily paired with solar PV (photo-voltaic) for completely free hot water.
  • Is light (under 60kgs) and portable – so is great if you rent or if you are moving house.
  • Can be used to boost existing or large-scale hot water systems, as well as with hydronic heating systems.


$1,924.00 incl GST

(no rebates available without tank)

Click here to order an Earthworker Solar Hot Water System, get a quote, or make an enquiry.

Essential component for retrofits
If you are purchasing the BOLT-ON heat pump to convert your current hot water heater storage tank to solar, you will require a Solar Return Line Connection with a Temperature Probe (SRLCTB). This connects your existing storage tank to the BOLT-ON Heat Pump as well as enables the tank to have a temperature probe. Price of the SRLCTB is $77.00 incl. GST

Siddons QIK Kit (Plumbing Valves & Components) – Recommended
Siddons BOLT-ON is easy to install. To make things even easier, Siddons has developed a QIK Kit that we recommend you purchase with a BOLT-ON (if your plumber does not already carry it). It contains all the valves & parts your plumber will need to ensure a professional installation. Price of the QIK Kit is $297.00 (incl. GST).

Click here for QIK Kit details.

How does a heat pump work?

The BOLT-ON uses a reverse application of the technology found in household refrigerators, utilising the solar heat present in the air around the unit. The unit contains a refrigerant that boils at -26°C, This means that at any air temperature is hotter than this, the refrigerant liquid becomes a gas, which can be compressed. When you compress air it gets hot (like when you put your finger over a bike pump and pump!).
The BOLT-ON uses a very small amount of electricity in order to run a compressor. This compresses the refrigerant gas to superheat at 95°C. This heat is used to heat your hot water via the BOLT-ON’s Dynamic Cycle heat exchanger, and the water then goes to your water storage tank, ready to be used. For more information about heat pump technology click here.

CLICK HERE to download a detailed brochure for the BOLT-ON, which is designed by Australian company and Earthworker partner, Siddons Solarstream.

Hot water storage tanks

The BOLT-ON can be used with existing hot water storage tanks – just unplug your existing heating system and ‘bolt on the BOLT-ON’. However, if you need to buy a completely new system, or want to upgrade to the most efficient system possible, you can also purchase an industry leading Eureka’s Future ‘Solar Ready‘ stainless steel water storage tank, made in Dandenong (VIC). Purchasing a completely new system (BOLT-ON and tank) with our 250L or 315L tank packages qualifies you for significant government rebates.

Finance with bankmecu – helping you make the switch to solar

Through our partnership with Australia’s first customer owned bank, bankmecu, all Earthworker members are eligible for a special fixed low rate to help them make an effortless switch to solar. For more information on the special offer and details on how to apply, see:

The road to manufacturing in our own right

It is thanks to our unique partnerships with local small businesses, Everlast, Siddons Solarstream, and SolarArk, that Eureka’s Future is able to start production now, even before we establish the first Eureka’s Future factory in our own right.

Everlast has been manufacturing water tanks in Dandenong for years, and despite the overwhelming trend of sending production offshore, remains committed to supporting and maintaining local manufacturing. Earthworker is now starting to manufacture our high quality stainless steel water tanks through Everlast’s Dandenong factory. This allows us to start training workers and build our capacity to expand this process into our own factory in Morwell.

Through Australian company Siddons Solarstream, we have the rights to manufacture the BOLT-ON here in Australia. Siddons, like almost all other renewable energy companies, is producing their first batch of BOLT-ON’s overseas. We will take on manufacturing components of the BOLT-ON right here in worker-owned factories. As our capacity increases, we aim to manufacture more and more components of the BOLT-ON.

With your support, we can bring manufacturing jobs and skills back into our communities and build the renewable energy technology we need to address the climate crisis. Each system we produce and sell now is a step towards manufacturing in our own right in Morwell.

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