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Climate action: 12 steps to choosing a heat pump

Heat pumps are crucial for decarbonising our energy use. 

Here, we provide a roadmap for choosing a heat pump.

Heat pumps may not look like a hugely sexy technology, but what they do is pretty magical. 

Like fridges in reverse, they move heat from the air or ground outside into your home to warm your radiators or water. While they use small amounts of electricity to operate, they are a very low carbon way of heating your home overall. 

Heat pumps can also provide air conditioning, which may become more and more useful as we see more heat waves during the summer months. 

Compared to the most efficient gas boilers currently available, a heat pump will save on average over 2 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. Homes across the UK will therefore need to move to heat pumps if we are going to meet our net-zero goals.

How to choose a heat pump

Installing a heat pump is a major climate action you can take. It’s also a major decision in terms of investment, so here we provide a 12 point step-by-step guide on everything you need to do for getting a heat pump installed.

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

There are lots of different types of heat pumps, including air to water, ground source and hybrid heat pumps. Below we outline the different kinds.

Most people go for air source heat pumps, as they don’t require much space and can be fitted in almost any home. If you have a garden or large outdoor space, then you may also want to consider a ground source option.

Whatever heat pump you choose, they 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.

Types of heat pump

Air source heat pumps: air to water

Most of the heat pumps installed in the UK are air to water. 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 it can be fitted to a wall or on the gound, with space for a good flow of air around it.

All air source heat pumps do produce some noise, as they contain a fan, but the modern ones are much quieter: about 40 to 60 decibels, which is 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 meter 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 meters. 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.

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.

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.

Check out our guide to heat pumps to find out which companies you can buy from >

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. A retrofit 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 introductory page or a more detailed guide.

If you are a homeowner and want to arrange a retrofit assessment, you can contact Retrofitworks through their website 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 brand

Ethical Consumer’s guide to heat pumps rates and ranks the ethical and environmental record of 16 different heat pump brands, and tells you which types they offer.

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 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).

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. Some brands may offer a warranty extension at a cost.

Radiator with three pairs of feet in socks resting on it

4. Think about your insulation and radiators

Installing a heat pump is likely to require other changes to your home. Heat pumps produce less heat than a conventional system, so your house will usually need to be well insulated. You may also need larger surface radiators or underfloor heating.

It might be tempting to skimp on the insulation and just get a larger heat pump, but over time this will cost more (and the heat pump will take up much more space).

A good retrofit assessor will take this into account when giving you advice, as well as alternative types of heat pumps if better insulation or larger radiators aren’t an option for you.

5. Work out what you can afford

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.

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

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 3 or 4 times the cost of gas, so even though your heating will be 3 to 4 times more efficient, these are likely to cancel out if switching from a gas boiler. This is another good reason to make sure your home is well insulated first, overwise you may end up spending more.

6. Check whether you can get government support

Luckily, there are some government schemes to help with the cost of heat pumps. Schemes change from time to time, so it’s worth doing an internet search for the latest information.

UK 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 home owners, 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. More information is available on the government website >

Scotland: Home Energy Scotland loans

In Scotland, homeowners can get interest-free loans of up to £17,500 to help cover the costs for setting up renewables. For heat pumps specifically, you can get a £2,500 loan plus up to £7,500 in cashback. Find more information on the Home Energy Scotland website >

The Scottish government will also cover the cost of some warm home improvements such as insulation and renewables set-up if you meet certain criteria, for example you are a pensioner or have a child under 16 and receive passport benefits, or receive disability or carers allowance. More information available from Home Energy Scotland >

Landlords can also receive loans of up to £10,000 for installing heat pumps. Some loans will be subject to interest. If you are a tenant, you may want to send your landlord this information. Find out more >

7. Set a realistic goal

A heat pump is a long-term investment, and may not be something you can implement straight away. Luckily, they will be useful whenever you can afford one.

So why not set yourself a realistic stage-by-stage goal for saving? For example, ‘In two years time I’d like to be able to start insulating my home, so it’s heat-pump ready.’

Government support for such schemes may also improve over coming years.

side of house with man installing a heat pump

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.

Making decisions about heat pumps can also take a while: why not add steps like getting a retrofit assessment and applying for a government grant into your plan?

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 the Renewable Energy Assurance Ltd (REAL) and the Ground Source Heat Pump Association, which encourage high installation standards.

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. Energy Saving Trust explains how >

You should also tell your local district network operators (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. The Energy Network Association provides more guidance >

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.

The government has a full guide to registration on its website >

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.

Energy Saving Trust has an excellent in-depth guide to heat pumps >

Why is choosing a heat pump an important climate action?

Our heating accounts for around 14% of our total emissions. About 77% of that is from homes, 14% commercial buildings and 9% public buildings. Heat pumps are key to reducing these impacts.

Heat pumps are hugely efficient, which is why they are being viewed by so many as the key to decarbonising the UK’s heating. They are on average three to four times more efficient than a gas boiler, and will cut a household’s emissions by equivalent to one sixth of an individual’s entire yearly footprint.

Heat pumps are still rare in the UK. Only about 30,000 were installed in 2020 compared to about 1.5 million gas boilers. But internationally they are widely used. The UK must install 1.1million heat pumps every year between now and 2030 if we’re to meet our decarbonisation targets.

Climate Gap report

In October 2021, Ethical Consumer published a report looking at consumer action on climate change. It looked at ten key actions consumers must take for the UK to reach its emissions reductions goals, and how far we are from meeting them.

It found that without further action, we would miss all ten key consumer targets.

Our Climate Gap report used figures from the Climate Change Committee (CCC) – the group that advises UK governments on decarbonisation. The CCC has outlined a number of different decarbonisation scenarios. All its scenarios are strongly heat pump led.

Read a summary of the Climate Gap report >