Heat pumps
Heat Pumps for UK Homes
Efficient heating that uses energy from the air or ground: how it works, and whether your home may suit it.
- Free eligibility check
- Independent advice
- No obligation
Prefer to talk? 0121 838 3030
- £7,500 Grant towards an eligible heat pump (England and Wales)
- Most homes can be heated by a heat pump
- 3 types Air source, ground source, air-to-air
- Several units of heat for every unit of electricity
How a heat pump works
A fridge running in reverse, at the scale of a house.
- Takes heat from the outside air or the ground
- A compressor raises it to a useful temperature
- Delivers it to your heating and hot water
- Gives several units of heat per unit of electricity
- Good design matters more than the brand
How it works, in full Show less
Efficient home heating that uses energy from the air or ground. Find out how heat pumps work, whether your property may be suitable and what support may be available. Grant support through the Boiler Upgrade Scheme applies to England and Wales. Whether a particular property qualifies is assessed at application.
A refrigerator takes heat out of the food inside it and dumps that heat into your kitchen. A heat pump does the same thing in the other direction: it takes heat out of the outside air or the ground and delivers it into your home.
It does this with a refrigerant that boils at a very low temperature. Outside, the refrigerant absorbs heat and evaporates. A compressor then squeezes that vapour, which raises its temperature sharply. Indoors, the hot vapour gives up its heat to your heating system and condenses back to a liquid, and the cycle repeats.
Because the electricity is used to move heat rather than to create it, a heat pump delivers several units of heat for each unit of electricity it uses. That ratio is the coefficient of performance, and it is the single number that matters most for running cost.
The catch is that the ratio depends on how hard the system has to work. The bigger the gap between the outside temperature and the temperature of the water it produces, the harder it works. That is why heat pump systems are designed around low flow temperatures, and why the design work matters more than the brand of the box.
The three types used in UK homes
Air-to-air is a genuinely different proposition from the other two.
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Air source (air-to-water)
Heat from outdoor air, for radiators and hot water. The common choice.
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Ground source
Heat from buried loops or boreholes. Efficient and quiet; bigger groundworks.
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Air-to-air
Warm air straight into rooms. No radiators — and no hot water.
| Type | Heat source | What it heats | Suits | What you see |
|---|---|---|---|---|
| Air-to-water | Outdoor air | Radiators, underfloor heating, hot water cylinder | Most homes | Outdoor unit with clear airflow |
| Ground source | Ground loops or boreholes | Radiators, underfloor heating, hot water cylinder | Properties with land or drilling access | Trenches or boreholes; nothing visible afterwards |
| Air-to-air | Outdoor air | Warm air to rooms — no radiators, no cylinder | Homes without a wet heating system | Outdoor unit plus indoor units in each room served |
The three types, in full Show less
They are not variations on a theme. Air-to-air in particular is a genuinely different proposition from the other two.
Air source (air-to-water)
Takes heat from outdoor air and warms water for radiators, underfloor heating and a hot water cylinder. The common choice for UK homes.
Ground source
Takes heat from buried ground loops or boreholes. More efficient and quieter, but the groundworks are a project in themselves.
Air-to-air
Delivers warm air directly to rooms. No radiators, no cylinder — and no hot water, which is the part people miss.
Deciding between the two most common types? Our guide to air source vs ground source heat pumps compares cost, space, efficiency and disruption.
Is my home suitable?
Most UK homes can be heated by a heat pump. Five things decide how much has to change.
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Radiators
Some rooms may need bigger radiators. Existing pipework is usually fine.
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Insulation
Loft insulation and draught-proofing first. Perfect insulation is not required.
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Hot water
You need a hot water cylinder — space matters if you have a combi.
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Space and noise
The outdoor unit needs clear airflow and sensible siting.
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Electrics
Most homes need nothing unusual. Checked at survey.
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Ask your installer
What flow temperature is it designed for? Can I see the heat loss calculation?
Suitability, in full Show less
Radiators and the rest of the heating system
A heat pump runs at a lower water temperature than a boiler, so each radiator gives off less heat than it used to. The fix is more surface area: larger radiators, or higher-output ones, in the rooms where the calculation shows a shortfall. In many homes it is a handful of rooms rather than all of them.
Existing pipework is usually fine. Microbore pipework and heavily sludged systems need more attention, which a survey will pick up.
Insulation and heat loss
Reducing heat loss reduces the size of heat pump you need and the electricity it uses. Loft insulation and draught-proofing are cheap and almost always worth doing first. Solid wall insulation is a much bigger decision, and a good design can often work around a solid-walled property by sizing the emitters accordingly.
"Your home must be perfectly insulated before you can have a heat pump" is not true, and it puts people off unnecessarily.
Hot water
Air-to-water and ground source systems heat water for a cylinder. If the property has a combi boiler and no cylinder, space has to be found — an airing cupboard, a loft, or occasionally a purpose-built enclosure. In flats and small terraces this is often the binding constraint.
Where the equipment goes, and noise
An air source outdoor unit needs clear airflow and sensible positioning relative to windows and neighbours. Siting is governed by permitted development conditions in England and Wales, and your installer should tell you which route applies rather than leaving you to find out later. Ground source systems have nothing outdoors once the work is complete.
Electrical supply
Most homes need nothing unusual. Some need a consumer unit change, and occasionally the local network operator needs to be notified or involved. This is checked at survey.
Because a heat pump runs on electricity, people often ask about pairing one with solar panels. They work together in the sense that both connect to the same consumer unit, but the seasons work against the pairing: a heat pump uses most electricity in January, when a solar array generates least. They are two separate decisions rather than one, and neither depends on the other.
The question worth asking any installer
"What flow temperature have you designed this system to run at, and can I see the room-by-room heat loss calculation?" A confident answer to that tells you more than any brochure. There is more on this in our guide to whether a home is suitable for a heat pump.
Radiators or underfloor heating?
Both work. What matters is enough heat at a lower water temperature.
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With radiators
Most UK heat pumps run radiators. Usually only a handful of rooms need a larger one — the heat loss calculation shows which.
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With underfloor heating
Suits a heat pump very well. An advantage, not a requirement — worth it in an extension or where floors are being replaced.
Radiators and underfloor heating, in full Show less
With radiators
Most UK heat pumps run radiators. Because the water is cooler than a boiler’s, some radiators — often a handful of rooms rather than all of them — are replaced with larger or higher-output models. The room-by-room heat loss calculation shows exactly which.
With underfloor heating
Underfloor heating spreads heat over a large surface, so it suits the low flow temperatures a heat pump is most efficient at. It is an advantage rather than a requirement — usually worth it in an extension or where floors are being replaced anyway.
Heat pump running costs
There is no honest single figure. Four things decide yours.
- System design. Low flow temperatures and correctly sized radiators matter most.
- Your tariff. Heat pump or time-of-use tariffs can lower costs noticeably.
- What you replace. Oil, LPG or old electric heating compare more favourably than modern gas.
- Heat loss. Loft insulation and draught-proofing reduce the work the system does.
Running costs, in full Show less
A heat pump’s running cost comes down to how much heat the home needs, how efficiently the system delivers it, and what you pay for electricity. Efficiency is measured as a seasonal performance factor: how many units of heat you get, on average across a year, for each unit of electricity.
- System design. Low flow temperatures and correctly sized radiators make the biggest difference.
- Your tariff. Tariffs designed for heat pumps, or time-of-use tariffs, can lower costs noticeably.
- What you are replacing. The comparison with oil, LPG or old electric heating is usually more favourable than with a modern gas boiler.
- Heat loss. Loft insulation and draught-proofing reduce the heat the system has to provide.
We do not publish typical savings, because a figure that is true for one home can be wrong for the next. A proper survey with a heat loss calculation gives an estimate for your property. Our heat pump vs gas boiler guide explains the comparison in more depth.
Replacing your current heating
What changes depends on what heats your home now — and so does the support.
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Replacing a gas boiler
The most common switch. Some radiators may need upsizing; a combi needs a cylinder. The £7,500 grant may apply.
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Replacing an oil boiler
Often the strongest case — no more fuel deliveries. Up to £9,000 may apply until 31 March 2027.
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Replacing LPG heating
Treated like oil homes for the enhanced support, if every condition is met.
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Replacing electric heating
Usually means fitting pipework and radiators for the first time — a bigger project.
What changes, in full Show less
Replacing a gas boiler
The most common switch. Radiators may need upsizing, a hot water cylinder is needed if you have a combi, and the gas supply is usually capped. Running costs depend closely on your electricity tariff and system design. The standard £7,500 Boiler Upgrade Scheme grant may apply.
Replacing an oil boiler
Often the strongest case: no more fuel deliveries, and oil homes off the gas grid may qualify for up to £9,000 in enhanced support until 31 March 2027. The old tank is normally removed.
Replacing LPG heating
LPG homes off the mains gas grid are treated the same as oil homes for the enhanced support, provided every condition is met. The LPG tank or bottles can usually be removed once the new system is running.
Replacing electric heating
Moving from storage heaters or panel heaters to a heat pump usually means installing a wet heating system — pipework and radiators — for the first time, which makes it a bigger project. The standard grant may apply, but not the off-gas uplift.
What installation involves
Five stages. The design stage decides how well it performs.
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Step 1: Survey
Room-by-room heat loss calculation.
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Step 2: Design
Flow temperature, radiators, where the unit and cylinder go.
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Step 3: Quote
Scope, price and grant application.
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Step 4: Install
Several days for air source; controls set up.
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Step 5: Settle in
Runs gently for longer; controls tuned to you.
Each stage, in full Show less
1. Survey and heat loss calculation
Room by room, the installer works out how much heat the property loses at a design outdoor temperature. This sets the size of the heat pump and the size of every radiator — it is the foundation of everything that follows.
2. System design
The design fixes the flow temperature the system will run at, which emitters need changing, where the outdoor unit and cylinder go, and what the pipework and electrics need. Ask to see it. A design that shows its working is the best predictor of a system that performs.
3. Quotation and decisions
You get a scope and a price. This is also the point at which grant eligibility is assessed, and where the installer submits a scheme application if one applies.
4. Installation and commissioning
Typically several days for an air source system, longer where groundworks are involved. Commissioning sets the controls and the weather compensation curve, and this is where a good installation is separated from a merely finished one.
5. Living with it
A heat pump runs gently for longer rather than in short bursts. Expect a short settling-in period while the controls are tuned to how you actually use the house.
Heat pump grants
The Boiler Upgrade Scheme applies in England and Wales.
- £7,500 for an eligible air source or ground source heat pump
- £2,500 for air-to-air in homes
- Up to £9,000 for off-gas homes replacing oil or LPG, for a limited period
- Lower income in England? The Warm Homes: Local Grant may cover a heat pump
- Installer-led: the grant comes off the price — you do not apply yourself
Grant details, in full Show less
Air-to-water and ground source heat pumps currently attract £7,500 where the installation qualifies, and air-to-air systems £2,500 in residential properties. Up to £9,000 may be available for off-gas-grid homes replacing oil or LPG heating, for a limited period. Lower-income households in England may also be able to get a heat pump through the Warm Homes: Local Grant.
The scheme is installer-led: an MCS-certified installer applies on the property owner's behalf and the value is deducted from the installation cost. Full detail is on our heat pump grants page, and the criteria on the eligibility page.
Do heat pumps work in cold weather?
Yes. They extract heat from air or ground that is colder than the inside of your home, which is what a refrigeration cycle is for. Efficiency does fall as it gets colder outside, which is why a system is sized against a design outdoor temperature rather than an average one.
Do I need underfloor heating?
No. What matters is that the emitters can give off enough heat at a lower water temperature, so some radiators are usually upsized. Underfloor heating suits a heat pump very well, but it is an advantage rather than a requirement.
Are heat pumps noisy?
An air source outdoor unit has a fan and is audible close up, comparable to a quiet conversation at a short distance. Position matters, and there are siting rules that a competent installer will work to. Ground source systems have nothing outdoors at all once the work is finished.
Will I need a hot water cylinder?
For an air-to-water or ground source system, yes — they heat water for storage rather than instantly. If the property currently has a combi boiler and no cylinder, finding space for one is one of the first practical questions to settle.
How long do heat pumps last?
Manufacturers generally expect a service life in the region of two decades for the heat pump itself, with an annual check. A ground array lasts considerably longer than the heat pump connected to it.
Is a grant available towards the cost?
In England and Wales, the Boiler Upgrade Scheme may contribute towards an eligible installation. Eligibility depends on the property, the existing heating system and the technology, and is confirmed when the installer applies.
Thinking about a heat pump for your home?
Tell us about the property and what heats it now, and we will come back to you about the options.