The complete guide to heat pumps for flats

• Individual flats generally require smaller heat pumps
• There are six government grants available for heat pumps
• You need the freeholders’ permission to install a shared heat pump for flats 
• It is important to choose the right type and size of heat pump

Heat pumps are becoming a more common feature in both homes and flats.

They can gather heat from the air, ground and water, turning it into a clean, unlimited source of energy. 

Most of the conversation around heat pumps currently centres around houses, but it’s also possible to install heat pumps in flats.

In this article, we take a look at how that works and answer the following questions: 

• How much does a heat pump in flats cost?
• Will a heat pump save you money on your energy bills?
• What government grants for heat pumps are available?

If you’re already clued up on heat pumps and want to get in touch with an installer, fill in our short form with a few details, and we’ll pass them on to certified heat pump installers. They’ll then reach out to you with their best prices. 

Can you install a heat pump in a flat? 

Yes, it’s possible to install heat pumps in flats, but it can be complex. 

Firstly, you can either choose an air source heat pump or a ground source heat pump. 

Air source heat pumps extract heat from the air to heat both your flat and your hot water. They can extract heat from temperatures as low as -15 degrees C. 

Ground source heat pumps, meanwhile, extract heat from the ground and use it to heat radiators, underfloor heating systems and hot water. 

These are typically used for a block of flats, as can some air source heat pumps, but these are predominantly used for single flats.

Air source heat pumps for flats

Individual flats usually require smaller air source heat pumps that you would install for a house. This is because flats generally have less indoor space to heat.

An air source heat pump is incredibly efficient for warming a flat or apartment. 

If you have access to at least 1sq metre of outdoor space, you can install an air source heat pump for your flat. This is so long as you don’t mind having an outdoor heat pump unit in that outdoor space. If you only have a small balcony for example, you might not want a heat pump unit to take up space on it.

If you don’t have a balcony, you can still install an air source heat pump on the outside wall of your flat, but easy access is required.

If you have a flat with a garden, then an air source heat pump is probably your best option. 

It’s important to note that air source heat pumps are considered a permitted development, so you won’t need to apply for installation permission. However, this is only true if you are the freeholder of your property. 

There are also options of using a portable heat pump. These are plug-in models that can heat or cool a single room. 

Ground source heat pumps for flats

To install a shared ground source heat pump in a block of flats, the building must have sufficient outdoor space, a minimum of 100sq metres, which means that your garden would need to be 10m long by 10m wide (or roughly 33ft by 33ft). 

A shared ground loop – the portion of the ground source heat pump that draws heat from the earth – is trenched in the ground near the block of flats and connected to individual indoor units installed inside each flat. 

Like any other heat pump system, a ground source heat pump is considered a permitted development for property owners. 

Each flat has access to their own indoor unit and is billed according to their electricity use.

Is it cost effective to install a heat pump in a flat?

One of the disadvantages of installing a heat pump system in a flat is the payback period. 

On average, a heat pump system pays for itself in seven years, but it can vary depending on the size of the property and the use of the system.

An air source heat pump currently costs around £10,000, while a ground source heat pump costs £24,000, on average. The savings period for a three-bedroom house after 20 years is £4,082. 

However, in the long run, the system will always pay for itself due to its high energy efficiency. In addition, heat pumps contribute to the improvement of the environment by using a technology that reduces the emission of polluting gases. 

Will I need to upgrade my flat? 

It’s unlikely you will have to upgrade your flat. Heat pumps are designed to operate most efficiently at a lower, but consistent temperature. This is in contrast to traditional gas boilers, which deliver a rapid blast of high heat when they are fired up. 

For this reason, it is essential to ensure that heat loss in your building, including in communal areas, is made as low as possible in order to gain the maximum efficiency and benefit from your heat pump. 

The good news is that compared to houses, flats are likely to have better insulation because they have fewer external walls.

If you already have a balcony or garden, you most likely won’t need to upgrade your flat. However, an upgrade might be needed if you’re installing a ground source heat pump for the whole building. 

How much does a heat pump for a flat cost?

The price of an air source heat pump can vary between £4,500 and £10,000, according to EDF Energy, which will be dependent on several factors, such as: 

• How powerful the unit is
• The brand of the heat pump
• Government grants
• Installation costs 

If you live in England and Wales, heat pump costs are inclusive of both installation and a government grant of £7,500, which is available through the Boiler Upgrade Scheme. 

Scotland also has installation and a government grant of £7,500 included, but this is run through the Home Energy Scotland grant.

If you live in Scotland, you can also apply for an interest-free loan of up to £7,500 to cover the remaining installation costs. 

Ground source heat pump costs for shared usage vary between £4,500 and £49,000. The lower cost will be for a compact heat pump, while the more expensive heat pumps will be one for your garden or for shared buildings. These costs are also inclusive of installation costs. 

These costs will also be dependent on several factors, including: 

• The size of the block of flats
• How many flats are in a block
• The complexity of the installation 

If you want to find out more about heat pump costs, check out our full guide. 

An air source heat pump installed on an exterior wall

What are the first steps for installing a shared heat pump?

To install a shared heat pump for a block of flats, you’ll need the freeholders’ permission.

If you’re renting, this will most likely be the landlord, the building’s managing company, or the corporation who owns the land. 

Shared heat pump technology is still relatively new, so there are only a few installers who are qualified for this type of installation. 

For example, Vaillant – one of the largest heating technology developers in Europe – only showcased its first heat pumps designed specifically for flats in March last year. 

Kensa has successfully installed shared ground source heat pumps in flats. In February 2024, the Cornwall-based installer announced it was launching a new concept ground source heat pump, the ‘Shoebox NX’. 

The electric heat pump is designed to be connected to a network of pipes, similar to the gas network, that draw ambient heat from holes drilled deep into the ground and use it to power the pumps to produce heat. 

If you are considering replacing a communal boiler with a heat pump, it’s important to ensure you have the support of all the residents, as they will be sharing the costs. This will probably require an installer to give cost indications and the impact a heat pump will have on energy bills.

What government grants are there for heat pumps in flats?

There are currently six government grants available for heat pump installations for individual homes. 

• The Boiler Upgrade Scheme
• ECO4
• Warmer Homes Scotland
• Private Rented Sector Landlord Loan
• Nest Wales

These grants weren’t created specifically for flats, but there’s no stipulation in them that people who live in flats can’t use them, as long as they meet the eligibility criteria. 

You can see a summary of the available schemes in the table below, but if you need more detail, head to our page on heat pump grants. 

Private Rented Sector Landlord Loan (Scotland)

While there are no specific grants for flats, the Private Rented Sector Landlord Loan is designed to help registered, private landlords in Scotland improve the energy efficiency of their properties. 

Funding is available for businesses owned: 

• By an individual in their capacity as a sole trader
• By some or all of the members of an incorporated association in trust for the association
• By either: A limited company, a limited liability partnership, a trust, a partnership, a registered society under the Co-operative and Community Benefit Societies Act 2014, or a Scottish Charitable Incorporated Organisation, or
• In any other capacity which Energy Saving Trust or the Scottish Government considers to be a business

Landlords can apply for up to two renewable systems per property, worth up to £17,500 in total, plus an energy storing system up to a maximum of £6,000. 

This loan applies to multiple different types of renewable energy sources. For heat pumps, this loan is a maximum of £10,000. 

Case study: High rise apartments in Thurrock

Three tower blocks, containing 273 flats, were retrofitted with shared ground source heat pumps between 2022 and 2023. The outdated storage heaters in the flats were replaced with individual heat pump units, connected to a shared ground loop. 

The project was a collaboration between Thurrock Council in Essex, which owns the tower blocks, and ground source heat pump installers, Kensa.

It was funded in part by the government’s Social Housing Decarbonisation Fund, which awarded Thurrock Council £3.2m for the installation. 

Residents of the flats have reported that the new system is better at keeping their homes warm.

According to Kensa Contracting, replacing the energy inefficient storage heaters with a ground source heat pump helped residents in a two-bedroom flat save around £952 a year on their energy bills. 

Next steps

It might be trickier to install heat pumps for flats compared to houses, but that’s not because flats are poorly suited to them. 

As we’ve discovered, you can install a heat pump in any type of property, it’s all about what is right for you.

What’s more, a 2020 government-funded project called The Electrification of Heat found that all properties are suitable for a heat pump.

The project was designed to test heat pumps in different types of homes, and they were successfully able to install heat pumps in everything from flats to Victorian houses. 

Remember, if you’re in a small flat with a balcony or garden, an air source heat pump is probably your best option.

If you live in a flat with little or no access to outdoor space, you might want to look at an electric alternative to a heat pump.

However, if you’re a landlord who owns an entire block of flats, which has some land attached to it, then you could have the option to install a larger air source or ground source heat pump. 

If you want to find out more about which heat pump is best for your property, we can help.

Simply fill in our form and we’ll pass them onto the professional heat pump installers. They’ll reach out to you directly with quotes and expert advice. 

Summary 

• The average two-bedroom flat needs a 5kW (kilowatt) air source heat pump, or a 4kW ground source heat pump
• The size of heat pump a flat needs varies, depending on how big and well insulated the flat is. Smaller flats need smaller heat pumps, and larger/poorly insulated flats need larger heat pumps
• Landlords will not be forced to install heat pumps, but it looks like gas boilers will eventually be phased out, so it makes sense to consider your options now.
• Heat pumps produce some noise while operating, but this is a maximum of 40-60 decibels. For context, this is roughly the same noise level as a fridge.