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Eco Heat Pumps

How to find an eco friendly heat pump company. We rate the ethical and environmental record of 18 heat pump brands.

We look at the different types of heat pumps, their efficiency and performance, environmental impact, running costs and grants. Plus we give our Best Buys and recommended buys. We also shine the spotlight on MasterTherm.

About Ethical Consumer

This is a shopping guide from Ethical Consumer, the UK's leading alternative consumer organisation. Since 1989 we've been researching and recording the social and environmental records of companies, and making the results available to you in a simple format.

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What to buy

What to look for when buying a heat pump:

  • Does it have good efficiency ratings? This will be listed as A+++ and also sometimes as the SCOP (Seasonable Coefficient of Performance) or SFP (Seasonal Performance Factor) number. The better the efficiency, the more energy you will save and the more you will help the climate.

  • Does it have a good supply chain policy? Heat pumps contain materials sourced from all over the world. Buying from an electronics company with a strong policy is a good step.

Best Buys

Kensa is the Best Buy brand for ground source heat pumps. Although it did lose marks in several categories, it scored a middle rating for supply chain management, and only sells products which are environmental alternatives, making it an ethical frontrunner in this industry.

Recommended Buys

Ground source heat pumps: MasterTherm, Stiebel Eltron, and Vaillant.

Air source heat pumps: MasterTherm, Grant, Stiebel Eltron, and Vaillant.

These recommended buys (like all heat pump manufacturing companies) scored poorly in significant ratings such as Supply Chain Management and Pollution & Toxics. However, they’re the best of the bunch because they didn’t score worst ratings in our financial categories like Tax Conduct and Director’s Pay – issues that are rife in the electronics sector.

What not to buy

What to avoid when buying a heat pump:

  • Does it lack a strong conflict minerals policy? The big electronics companies have a significant influence on what goes on in regions where mineral sourcing is connected to human rights abuses.


Companies to avoid

We recommend avoiding Samsung and Mitsubishi, which each lost marks across almost all our ethical rating categories.

  • Samsung
  • Mitsubishi

Score table

Updated live from our research database

← Swipe left / right to view table contents →
Brand Score(out of 100) Ratings Categories

Grant heat pumps

Company Profile: Grant Engineering (UK) Ltd

MasterTherm heat pump

Company Profile: MasterTherm UK

Vaillant heat pumps

Company Profile: Vaillant Group UK Limited

Stiebel Eltron heat pump

Company Profile: The Stiebel Eltron Group

Kensa heat pumps

Company Profile: Kensa Group Ltd

Viessmann heat pumps

Company Profile: Viessmann Limited

CTC heat pumps

Company Profile: Enertech Group

Danfoss DHP-H Heat Pump

Company Profile: Danfoss A/S

LG heat pumps

Company Profile: LG Electronics Inc

Nibe heat pumps

Company Profile: NIBE Energy Systems Limited

Calorex Heat Pumps

Company Profile: Dantherm Group A/S

Dimplex heat pumps

Company Profile: Glen Dimplex Group

Hitachi Yutaki heat pump

Company Profile: Johnson Controls International plc

Daikin heat pumps

Company Profile: Daikin Industries Ltd

Panasonic heat pumps

Company Profile: Panasonic Corporation

Worcester Bosch heat pumps

Company Profile: Worcester Heat Systems

Mitsubishi Electric Ecodan heat pumps

Company Profile: Mitsubishi Electric Corporation

Samsung heat pumps

Company Profile: Samsung Electronics Co Ltd

Our Analysis

Heat pumps are still relatively new in the UK, and with different types available it can be confusing to know what to look for if you want to buy an eco-friendly ethical heat pump.

Our research looks at different factors, and whilst no brands are incredibly high scoring, there is a clear difference in ethics from the top to the bottom brands, and some should be avoided.

What are heat pumps?

A survey in December 2018 showed that less than a third of people know what heat pumps are.

Technologically, they are just fridges in reverse. They move outside heat – either from the air or from the ground – into your house. They are astoundingly efficient, delivering three to four units of heat for each unit of electricity needed to run them.

They can reduce your carbon footprint from heating by two-thirds or more, making them the eco-friendly option for home heating.

How common are heat pumps in the UK now?

Heat pumps are still rare in the UK. About 55,000 were installed in 2021 in the UK, making up just 3% of new heating systems installed that year.

But in some areas like North America, parts of Europe, and China, they are widely used. 29% of heating demand in Sweden is covered by heat pumps (showing they can work effectively in cold climates), and in the US 40% of new family homes have heat pumps.

The UK government hopes to reach 600,000 heat pump installations per year by 2028 – an eleven-fold increase from 2021. (In our last guide two years ago, a twenty-fold increase was needed, so installations are on the up).

But, there is a shortage of heat pump installers.

In 2022, the Social Market Foundation released a report called ‘Installing for time?’, which outlines how installing a heat pump requires training in significantly different techniques from those involved in fitting and maintaining a gas boiler.

The UK lacks trained installers and one of the report’s recommendations is that policymakers launch an engaging recruitment campaign to attract new installers.

Why make the switch to heat pumps?

Mike Childs, Head of Science, Policy and Research at Friends of the Earth says,

    “I got an air-source heat pump two years ago and it’s kept our home warm, including through a cold north-of-England winter. It extracts heat from the air outside, even when it’s freezing cold, and uses it to heat the water in our radiators and in our hot water tank. It doesn’t make the water as hot as a gas-fired boiler, so to ensure our house is warm enough it runs for longer and we’ve increased the size of our radiators. The heat pump itself is in our backyard where it hums away quietly.”

Heat pump companies

We cover 18 manufactures of heat pumps in this guide. Some make several types of heat pumps, some only make one or two types. The table below shows which heat pump company makes what kind of heat pump.

Which company makes what kind of heat pump?
Brand Air source Ground source Hybrid
Calorex Yes Yes  
CTC Yes Yes  
Daikin Yes Yes Yes
Danfoss Yes Yes  
Dimplex Yes Yes  
Grant Yes   Yes
Hitachi Yutaki Yes    
Kensa    Yes  
LG Yes    
MasterTherm Yes Yes Yes
Mitsubishi electric Yes Yes Yes
Nibe Yes Yes  
Panasonic Yes   Yes
Samsung Yes    
Stiebel Eltron Yes Yes  
Vaillant Yes Yes Yes
Viessman Yes Yes Yes
Worcester Bosch Yes Yes Yes

side of house with man installing a heat pump

How eco-friendly are heat pumps?

Compared to the most efficient gas boilers currently available, a heat pump will save on average over 1.5 tons CO2 per year. That’s big, considering that the annual carbon footprint for someone in the UK is on average 12 tons per year.

And even if you aren’t planning to get a heat pump, it’s valuable to find out about them because pretty much every route to avoiding climate meltdown includes heat pumps playing a significant role.

The International Energy Agency (IEA) says that heat pumps currently meet around 10% of the global heating need in buildings. According to its Net Zero Emissions by 2050 scenario, however, the global heat pump stock needs to double to 20% by 2030 and increase 10-fold by 2050.

The Climate Change Committee's (CCC, the official body that advises the UK government on decarbonisation) pathways to net-zero all see the majority of UK homes being heated with heat pumps by 2050.

By 2028, at least a fifth of homeowners replacing boilers at the end of their lifetimes will need to choose a heat pump for Government targets to be met.

Heat pumps, refrigerants and greenhouse gas emissions

Heat pumps use refrigerants, and the most common traditionally has been a hydrofluorocarbon (HFC) called R410A, which has over 2000 times the warming effect of CO2 per molecule.

Although it should be possible to recover the refrigerant at the end of life, there may be some leakage.

The ‘F gases’ – very powerful greenhouse gases like HFCs – accounted for 3.02% of UK greenhouse gas emissions in 2020, and HFCs form 95.1% of that. But UK F gas emissions have decreased by 11% since 2016, due to regulation.

Potential replacement refrigerants include propane and CO2. Vaillant for example, is switching to propane, which has a GWP (global warming potential) of 3, or to ammonia or CO2. But some of these have their own problems, such as being unacceptably toxic or significantly less efficient, meaning that more electricity is used.

And while the grid is still significantly based on fossil fuels, this can result in a higher carbon footprint than the ones with high GWPs (although once the grid is fully decarbonised, we won’t need to worry as much about efficiency, although the toxicity issues still remain).

According to the Climate Change Committee, “if existing standards are maintained, the greenhouse gas savings of a switch to heat pumps are orders of magnitude higher than the additional F-gas [HFC] emissions.”

Given the complexity and that the climate impact is small, we decided not to rate companies on the basis of the refrigerants they use in their heat pumps.

What are the running costs of heat pumps?

There is different information available about heat pump running costs. And the relative cost of gas and electricity is changing, so this may change. Electricity costs are rising, but not as much as gas.

How do heat pump companies rate on ethical and environmental issues?

The core of our ratings is looking at a variety of ethical and environmental issues to see how companies perform. Here we highlight how heat pump brands rate for three different aspects.

Carbon management and reporting

Despite manufacturing this emissions-reduction technology, few companies scored well in our ranking of carbon management and reporting for their own operations.

Our criteria require, amongst other things, annual reporting on emissions and targets for reductions in line with international agreements.

Panasonic received a best rating, and Hitachi Yutaki and MasterTherm a middle rating. The rest received a worst rating.

Company Ethos

MasterTherm was the only company to receive a positive Company Ethos mark because it appeared to only sell products that were innovative environmental alternatives.

Animal rights

Four companies lost half marks in the Animal Rights category, for the following reasons:

  • Panasonic and Samsung – sale of leather products.
  • Mitsubishi – owns Norwegian salmon farming company Cermaq, making it the world's major salmon farmer by volume.
  • Calorex – owned by a private equity firm that owns a ready meals company that includes meat products, without animal welfare policies.

Is my home 'heat pump ready'?

Matt Franklin of Carbon Coop raises a few considerations for designing an efficient system.

With a new grant for heat pumps – the Boiler Upgrade Scheme, launched in April 2022 in England and Wales – many people are asking whether they need to make significant investments in insulation to make their homes ‘heat pump ready’.

Whilst some say your home needs to meet PassivHaus standards, others say you can just go ahead.

What does ‘heat pump ready’ actually mean?

The reality is that without taking a look at your house as a system, a new heat pump won’t work efficiently. If you don’t make any changes you are likely to end up with a heat pump which is either oversized, too expensive, or not adequate to heat your home.

Getting an overly large heat pump might seem like a good way to avoid extra work, but it will cost more and take up more space.

With installations costing several thousand pounds, making general improvements to your home first can make a significant difference to the price of the pump and the running costs over its lifetime.

With an oversized heat pump and no other changes, you may still cut your carbon emissions (by eliminating gas) and have an efficiency broadly comparable to a gas boiler, but, to see lower bills, a more comfortable home and a radically reduced carbon footprint you need to do more.

Improving your home’s insulation, draught proofing, replacing some radiators, etc, means that you will be able to install a heat pump which is smaller both in size and in terms of energy consumption, quieter and overall simpler to run.

Using a rough demonstration generated from People Powered Retrofit’s home assessment tool, it's possible to see the potential of a low, medium and high impact retrofit, and the size of heat pump that could then be used i.e. small, medium and large.

  • Baseline scenario: Peak heat load = 11.1kW (large heat pump required)
  • Scenario 1 low impact retrofit: Peak heat load = 8.8kW (medium heat pump)
  • Scenario 2 medium impact retrofit: Peak heat load = 5.1kW (small heat pump)
  • Scenario 3 high impact retrofit: Peak heat load = 3.8kW (small heat pump)

Any kind of retrofit reduces the size of the heat pump required – but deep retrofit has a significant impact. So, whilst you don’t have to go for a deep retrofit before you install a heat pump, the more you can do the better.

So, should I get a heat pump?

If you’re worried about money, a heat pump is probably not an investment you want to make.

However, if you can afford the initial investment and are able to potentially risk spending a bit more on your energy bills, and care about the climate, then the answer is 100% yes – buy a heat pump!

It is one of the best things you can do to cut emissions and help the transition to renewables.

12 steps to getting a heat pump

Here we outline the main steps to think through if you are planning to get a heat pump.

1. Consider what kind of heat pump would work for you

Heat pumps are a substantial investment, so it’s important to make sure you get the right one. Air source heat pumps are on average around £6,500, while ground source will cost more like £13,500 including installation.

Air source heat pumps: air to water

Most of the heat pumps installed in the UK are air to water, as they don’t require much space. They provide both water and space heating. They can be installed on almost all properties, including flats. They are generally about the size of a fridge and require a place outside where they can be fitted to a wall or on the ground, with space for a good flow of air around them.

All air source heat pumps do produce some noise, as they contain a fan and compressor, but the modern ones are much quieter: about 40 to 60 decibels, which is similar noise levels to a fridge or dishwasher and therefore rarely a problem.

Air source heat pumps: air to air

Air to air heat pumps are just air conditioners that have been put into reverse. They blow hot air into your house, so they only do space heating. You would need something else for hot water. Air to air pumps do have some advantages. The pumps are cheaper and have good efficiency. Since they don’t use radiators, you won’t need to install bigger ones, although you may need ducting (pipes) in order to carry the hot air around to different rooms.

Ground source heat pumps

Ground source heat pumps take heat from the ground instead of the air, using pipes buried outside the house. This makes them much more efficient, and silent. However, they are more expensive and only suitable for a limited number of homes because they require considerable amounts of outside space.

Horizontal ground source heat pumps need pipes that are buried in a long trench in your garden, about a metre deep. You’ll need an area about twice the size of your home. Vertical ones have pipes in a series of boreholes instead – down to 70 or 100 metres. This means they require much less garden space. But they are far more expensive to install, and you will need space for the drilling machinery.

Hybrid heat pumps

Hybrid systems combine a heat pump and a traditional boiler. The theory is that the heat pump does most of the work, but the boiler helps out in particularly cold weather, when heat pumps struggle. One study shows that hybrid heat pumps potentially save 30% of GHG emissions compared to typical gas condensing boilers over a lifetime of 20 years.

Hybrids have some advantages. For the UK as a whole, they would take pressure off the electricity supply during peak times. However, they would still be relying to some extent on the grid.

A hybrid system can also be cheaper if you already have a boiler and are just installing a heat pump to work alongside it, because you may get away with a lower capacity heat pump and not replacing your radiators.

Gas fired and water-source heat pumps

You can also get gas-fired heat pumps. They do use less gas than boilers, but aren’t massively cheaper than electric ones, so there doesn’t seem much point in getting one: better to get off gas altogether if you can.


A roof-mounted air source heat pump has reportedly been installed for the first time in the United Kingdom, as part of a pilot project at the University of Salford. The hope is that, if it proves effective, this might overcome the issue of size and location for many homeowners, enabling more to make the switch.

2. Look at getting a retrofit assessment

If you’re unsure what heat pump would work best in your home and whether you have the right set up for it, you may want to get advice from an installer or retrofit assessor.

A retrofit assessment will consider all possible energy saving measures in your home, including heat pumps, insulation, and other steps. An assessor will visit your house, speak to you about how you use the space and your own needs and recommend possible changes. They will estimate costs and carbon savings for each option, and say what stages you could make the changes in. TrustMark has an page on retrofitting including a guide to download and a video.

If you are a homeowner and want to arrange a retrofit assessment, you can contact RetrofitWorks to arrange an initial appointment. TrustMark also has a directory of tradespeople, including builders and retrofit assessors. A well-qualified assessor will have trained with a trusted specialist retrofit training body, such as the Retrofit Academy.

3. Choose a specific heat pump model

When deciding on a specific model you’ll probably want to consider: the size of the heat pump, its efficiency, and its noise-levels.

The main measure of a heat pump’s efficiency is called the coefficient of performance (COP). It measures how many units of heat you get out per unit of energy you put in. Ground source heat pumps average a COP of around four, and air source about three.

However, the COP varies depending on the weather. So, when you’re comparing individual pumps, you want to look at the average COPs they manage over a heating season. This is either given as the Seasonal Coefficient of Performance (SCOP) or the Seasonal Performance Factor (SPF). Heat pumps also come with energy ratings based on their SCOP. These range from A+ to A+++ (the more pluses the better).

Best Buy Kensa, and recommended buys Vaillant, Stiebel Eltron, MasterTherm and Grant all have A+++ rated heat pumps in their product range. The energy label for different brands and products can be found on their websites.

When deciding on a specific heat pump model, also consider the warranty offered. A well-maintained heat pump should last around 15 years, so it’s worth getting a model that’s covered for a while.

4. Think about your insulation and radiators

Improving your home’s insulation, draught proofing, replacing some radiators, etc, means that you will be able to install a heat pump which is smaller both in size and in terms of energy consumption, quieter and overall simpler to run. You may want to install larger surface radiators or underfloor heating. You can also visit the Carbon Coop website to find out more about the debate on how much insulation is required to effectively fit a heat pump.

5. Work out what you can afford

Unfortunately, heat pumps – and the required insulation – can be expensive: from £6,500-£17,000. Energy Saving Trust recommends you get quotes from at least three different installers to understand the potential costs.

If you visit the website of UK innovation charity NESTA, you can find a calculator to estimate the cost. You enter the information such as which part of the UK you live in, property type, number of bedrooms and other variables. It then states which type of heat pump you could install, which government grant (see point number 6 below) you might be eligible for, and an estimated price range. It’s based on statistical modelling of installations recorded by MCS.

Remember to include associated costs such as any additional home insurance costs (see number 11).

Unfortunately, even though you’ll save a lot of energy by using a heat pump, you’re unlikely to see any cost savings from this at the moment. Electricity is currently about three or four times the cost of gas, so even though your heating will be three to four times more efficient, these are likely to cancel out if switching from a gas boiler.

The Government’s ambition is to bring heat pump costs down by between 25-50% by 2025, and towards parity with gas boilers by 2030. It has, however, been argued that this seems unrealistic.

The Climate Change Committee estimates 2023 costs for heat pump capital and installation to be £12,000, which is down 7% from 2019.

6. Check whether you can get government support

Government schemes are key in helping many people afford the cost of heat pumps. Schemes change from time to time, so it’s worth doing an internet search for the latest information.

England and Wales: Boiler Upgrade Scheme

The government is providing grants for heat pumps in England and Wales under the Boiler Upgrade Scheme. The grant is available for homeowners and can give you £5000 off the cost and installation of either an air source or ground source heat pump.

Your installer will need to apply for the grant for you, so make sure to speak to them about it.

Scotland: Home Energy Scotland loans

In Scotland, grant funding for heat pumps is up to £7,500 or £9,000 for households which qualify for a rural uplift. The remainder of funding requested can be taken up as an optional interest-free loan.

7. Set a realistic goal

A heat pump is a long-term investment and may not be something you can implement straight away.
So why not set yourself a realistic stage-by-stage goal for saving?

8. Decide your timeline

You may want to decide when you’d like your heat pump by and map out a timeline. If you need internal work to your home, such as new radiators, it’s important to get this done at a moment that suits you.

9. Find a good installer

Make sure you use an installer who has been accredited through the Microgeneration Certification Scheme. If in Scotland, you can search for information and customer reviews on MCS installers in your area through the Renewables Installer Finder.

It is a good sign if they are also registered with other organisations and bodies, such as Renewable Energy Assurance Ltd (REAL) and the Ground Source Heat Pump Association, which encourage high installation standards.

You can also read the government-funded guide 'Heat pump talk' which shows you how to have effective conversations with heat pump installers from start to finish.

10. Think about planning permission and registration

Most heat pumps do not require planning permission. However, there are some exceptions, particularly if you live in a listed building or conservation area, so it’s good to check with your local planning department.

You should also tell your local district network operator (DNO) about your heat pump plans. They are the company that brings electricity to your home. Your installer should have all the information you need to complete the DNO’s forms.

Once your heat pump has been installed, it will need to be registered with the Microgeneration Installation Database (MID) within 10 days of installation. Your installer should do this for you.

You should also receive certain paperwork from your installer, including a Building Regulations Completion Certificate, MCS Certificate and Heat Pump Handover Pack.

11. Check your insurance policy

Make sure your insurance policy covers any changes you plan to make to your home. Your insurance company should be able to give you a quote if it doesn’t cover you already.

12. Find out about maintenance

It’s important to maintain your heat pump to make sure you get the most life out of it – which should be 15 years or more. Luckily, maintenance is fairly straightforward: ask your installer to write down exactly what you need to do.

Many manufacturers offer a 10-year warranty, and some will offer an extension at a cost. Check whether you need to do anything to ensure that your heat pump remains compliant, for example getting it serviced each year.

Company behind the brand

MasterTherm is a problematic brand in this guide because it lacks transparency. It appears to be based in the Czech Republic and sells its products to a range of European countries, and in the UK, it’s distributed by a company called Thermal Earth.

No further information about its ownership appeared to have been published. As such, we rated it as a large company, and so expected more than we would for a small or medium company.

It still appears to be at the better end of a not great bunch of brands in this guide, but we encourage MasterTherm to publish more transparent information about its ownership structure and revenue.

Want to know more?

If you want to find out detailed information about a company and more about its ethical rating, then click on a brand name in the Score table. 

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