Thermodynamic Hot Water Systems

Thermodynamic Hot Water is the next generation technology for heating your hot water, but is it right for you?

Imagine a new type of solar panel that could heat your hot water day and night, all year round, regardless of the weather. This is the promise of thermodynamic panels.

Thermodynamic panels differ from thermal solar panels because they heat a refrigerant rather than water. This lower operating temperature allows them to harvest heat from the atmosphere rather than from the sun.

The refrigerant enters the panels at a temperature of -22°C, so even on the coldest of UK winter days, they can still absorb the relative heat from the air.

How do Thermodynamic Hot Water Systems work?

Thermodynamic panels are effectively a refrigerator in reverse. They are actually closer to an air source heat pump than to solar thermal panels.

Refrigerant enters the panel and absorbs heat from the panel's surroundings converting it to a gas. This gas passes through a compressor, increasing it's temperature and is then pumped through a heat exchanger inside a hot water cylinder, where it heats the water to approximately 55°C.

A built in immersion heater uses electricity to boost the temperature to over 60°C every so often, to avoid risks such as Legionella.


Benefits of Thermodynamic Hot Water

The main advantage of thermodynamic hot water is a reduction in your hot water costs.

  • Save money on your fuel bill.
    Your fuel bills will come down as thermodynamic hot water systems provide 100% of a property's domestic hot water requirements.
  • Not reliant on weather/sunlight.
    Thermodynamic hot water systems create hot water all year round, even when it's raining or snowing and at night.
  • Highly efficient.
    Thermodynamic hot water systems have the highest coefficient of performance (COP) amongst each of the alternative water heating technologies.

So what's the catch?

  • Not currently covered by Green Deal or RHI.
    The Department of Energy and Climate Change is gathering information on performance and on the establishment of standards for these products. At present there is not an established methodology to test and demonstrate their performance and so they are not currently supported under the Renewable Heat Incentive.

In November 2012 the Micro-generation Certification Scheme (MCS) issued the following statement about Thermodynamic products:

MCS has completed an initial review of thermodynamic products (including solar thermodynamic panels), and as a result, MCS has now taken the decision to temporarily suspend the registration of solar thermodynamic products within the MCS installation database until requirements for the installation of this product type can be developed by the Scheme.

This decision does not mean that the products cannot be installed in the UK, simply that they cannot be registered within the MCS installation database. As such from 19th November 2012, no further installations will be allowed to be registered within the MCS installation database, and the product will be unavailable for selection.

MCS is already working with a number of manufacturers to develop requirements for this product type either by extension to the existing MIS 3001 or MIS 3005 or a brand new Scheme document if appropriate. Please click here to view a copy of a letter sent to all MCS certified solar thermal installers on 5th November 2012.

wall mounted thermodynamic panel

Is Thermodynamic Hot Water still viable without RHI?

Well, here's the thing. It totally depends on your circumstances.

Perhaps a few examples will make this easier to understand, and will help you see why Greentec are getting behind Thermodynamic Hot Water for situations where it is viable.

  • New Build/Renovation Project

    If you are in a situation where you are installing a new hot water system or replacement of the old system is a necessity, we would almost always recommend a Thermodynamic Hot Water System, because it's running costs will always be considerably lower than fossil fuel based systems.

    Also, in this situation, you are only having to find the difference in price between installing the thermodynamic system and installing a conventional system. If the savings are greater than the difference in price, you win.

  • Modern Efficient Gas Boiler

    Lets say you have a gas boiler and hot water system that does not need updating, the economics in this case will not add up. Even though the Thermodynamic system has significantly lower running costs than the most efficient gas boiler, the savings will not be greater than the initial installation cost over the lifespan of the system.

    Greentec will not recommend Thermodynamic Systems in this circumstance, unless you are considering becoming totally self-sufficient in terms of energy by combining several renewable technologies - Greentec's holistic renewable energy system - however our stance will probably change if/when thermodynamic systems qualify for RHI.

  • Oil, LPG, Coal and Electric

    If you are in a property using oil or LPG then the economics would most certainly dictate that you would save by ripping out the old and replacing with thermodynamic hot water, especially if combined with a Solar PV system to generate your electricity.

    Even without any subsidies, there is a strong case to switch to thermodynamic hot water, regardless of the state of your existing system.

  • Inefficient Gas Boiler

    If you are in the situation where you have an old, inefficient gas boiler, old copper tanks with poor insulation and were looking to benefit from technologies such as Solar PV, and your EPC rating was poor, then there may well be a case for looking into our holistic approach to renewable energy.

    Even without any subsidies, we can show you a way to switch to a combination of renewable technologies including thermodynamic hot water and have the whole system pay for itself.

roof mounted thermodynamic panel

What if you don't recommend Thermodynamic Hot Water in my circumstances?

It may well be that in your particular situation, we would recommend Solar Thermal Hot Water which is covered by RHI, rather than Thermodynamic Hot Water.

To really determine if Thermodynamic Hot Water is right for you we would recommend a free consultancy with one of our expert advisors. Once we know your situation, we can help you discover the right choices for you.

Call Greentec Now!

The best time to go for renewable energy is right now. The early adopters have gotten better tariff rates which are index linked and can last for 20 years. To find out how much you could save/earn from renewable energy, simply give us a call.


1. Call Us

Call Greentec on 0333 456 5000 to arrange a FREE consultation with one of our renewable energy experts. We come to you, at a time that suits you.


2. Your Consultation

Our experts will listen to your requirements, survey your property and make recommendations to get you the best solution for your circumstances.


3. Your Solution

If our recommendation ticks all the right boxes, then we're in business. We help you at each stage of the process to ensure you get the right system quickly and at the best price.