How a Hydrotherm heat pump works

Hydrotherm’s heat pump technology is both highly efficient and environmentally friendly.

This heating process explains how heat pumps got their name. Instead of directly heating water, heat pumps transfer or “pump” heat from one source to another. That’s why they are considerably more efficient that other hot water systems.

Heap Pump Technology

Heat pump technology itself is nothing new. The technology that is incorporated into every Hydrotherm has been around for over a 100 years in a multitude of appliances from refrigerators to air conditioners. The Hydrotherm hot water system is classified as an air to water heat pump and these types were first introduced over 50 years ago.

Unlike standard electric hot water systems, our system doesn’t use resistive elements to convert electricity directly into heat energy. These elements use up a lot of energy, requiring up to 3600 Watts per hour to run. Instead the Dynamic uses an average of 800 Watts per hour.

Instead of using electrical energy as the fundamental means of heating water, heat pumps use the heat that is generated naturally from the sun. That is why heat pumps are considered as a solar type of hot water system, as they use energy from the sun, even if they are not in direct sunlight.

Cost Saving FAQ's

Simply put, no. Heat pump technology has been around for over a 100 years in refrigerators and air conditioners. The heat pump water heaters were first introduced over 50 years ago in places such as Southern United States and Italy, where heat pumps are now well recognised and popular.

Air source heat pumps work exactly the same as your fridge or air conditioning unit, but in reverse. Heat pumps transfer heat from ambient air, then into the refrigerant and finally into the water inside the tank. A more detailed explanation is as follows:

  1. A fan draws in the ambient air and pulls it over the evaporator containing the liquid refrigerant.
  2. The energy from the air is absorbed and turns the liquid refrigerant into a gas.
    The gas passes into the compressor where the pressure is increased, generating enough significant energy to heat the water.
  3. The gas then travels through the closed loop in the water tank and transfers the heat.
  4. The gas then travels through the expansion valve where the pressure is reduced and the refrigerant returns to a liquid.
  5. The process begins again.

No, unlike solar panels and evacuated tubes, heat pumps don’t rely on direct sunlight. It uses the energy in air to generate heat. All that the system requires is uninterrupted air flow, click here to see the installation manual for positioning requirements.

All heat pumps by law must complete a low temperature operation and performance test to obtain their Watermark Sticker. The Hydrotherm has been tested down to -10°C and will still produce the required volumes of hot water.

Hydrotherm heat pumps are built specifically to withstand Australian conditions. The tank is made from vitreous enamel and has a current impressed electronic anode for maximum protection. Hydrotherm systems come with a full 6 year warranty on all aspects of the system. The expected lifespan of Hydrotherm systems are approximately 10-15 years. 

Please see our Servicing page for details regarding servicing Hydrotherm systems. 

The Hydrotherm unit itself does not require any regular maintenance. Every six months the relief valves should be released to ensure that they are releasing properly.

If the Hydrotherm unit is unused for two or more weeks, it is recommended that the PTR valve be released for approximately 10-15 seconds. However the PTR valve does not need to be released on a regular basis.

Hydrotherm systems have a built in memory to retain all the timers and settings. If power is lost due to a power failure or the shoulder tariff, the settings will be saved and no action is necessary. If the system is off for a long period of time, the clock may need to be adjusted but the settings will remain the same. 

The Hydrotherm DYNAMIC/X8 can heat water up to 70°C to comply with Government legislation and to meet Legionella requirements.

However if you are experiencing what you to be believe to be lower than expected hot water temperatures, please contact Hydrotherm on 1300 769 904 or at

It is always important to check your water quality, especially if you live in a cul-de-sac and if your appliances such as a kettle often require replacement. Warranty will be void if you are in a hard water area that records any of the below quantities:

  • • In excess of 600ppm of Total Dissolved solids
  • • Chloride levels exceed 250mg/L
  • • 6.0pH or lower

All of these can be controlled to an extent through the installation of a water filter. Please contact your plumber for further guidance on filters and installation.

The Hydrotherm has been tested, with a reading of 43dB. To give this some perspective it is similar to an outside air conditioning unit.

We recommend that all our clients set the in-built timers on their systems for three reasons. Firstly, all heat pumps run more efficiently during the days (when ambient air temperatures are higher) therefore saving more on the electricity bill. Secondly, having the system set on timers during the day will ensure that the system will not disturb anyone. Finally, like any appliance, the less you run your Hydrotherm system the better it is for the overall lifespan. 

Hydrotherm systems have a timer function with up to three timers, making the heating cycle very customisable. Setting timers will also ensure that you get the most out of your solar PV, if you have one installed. If you need any help at all with setting timers, please call us on 1300 769 904. 


350% efficiency rating reduces running costs versus gas and electric water heaters.

Registered Clean Energy product with annual carbon reduction rating of 3 tonnes.

Non-sacrificial impressed current anode provides protection in stoft and hard water conditions.

Intgergrate and maximise your solar PV with in-built timer controlled heat up cycles.

Dual heating technology with incorporated electric element to provide hot water up to 70°C.

R290 natural refrigerant with effectively zero global warming potential compared to synthetic


Rated Heating Capacity




Power Supply

Single Phase / 10Amp




1800mm(H) x 620mm(D)

Tank Thickness


Tank Max Water Temp


Net Weight


Element Rating


Tank Volume


Tank Material

Vitreous Enamel

Max Temp Operation


Tank Recovery

280 Minutes

Scroll to Top