It is widely acknowledged that air source heat pumps (ASHPs) and underfloor heating (UFH) partner together effectively. This is why heat pumps and underfloor heating systems are being specified and installed in properties which are striving to be eco-friendly, low carbon homes. In this guide, we will explain more about how these systems work, the benefits they can deliver and the funding available which can help reduce the installation costs.
Here in the UK, there is a growing demand amongst homeowners who want to heat their homes more sustainably. Low temperature heating solutions, such as air-to-water heat pumps, are one example of a low carbon heating system which does not burn fossil fuels but instead uses renewable energy to warm your rooms and provide hot water. You may have heard about heat pumps because they are becoming increasingly popular, with 63% more heat pumps installed in 2024 compared to 2023 (Source: Heat Pump Association) so let us help you learn more about heat pumps, underfloor heating and whether your home is ready for this more environmentally friendly heating system.
In this guide, we will:
- Explain how ASHPs and UFH works
- Share some of the benefits of installing UFH for heat pumps
- Explore some of the key installation considerations
- Summarise how to prepare for and maintain a heat pump
- Share information about grants and funding available
How do air source heat pumps work?
An air source heat pump (ASHP) heats your home by extracting heat energy from the air outside and converting this into energy that can be used to warm rooms and heat up water. The heat transfer process is achieved using a vapour compression cycle involving a refrigerant - usually R32 or R290 refrigerant.
Here is how the process works:
- Air Intake: The heat pump draws in the outside air.
- Evaporation: The air passes over an evaporator where the refrigerant is exposed to the air. The refrigerant, in liquid form, then boils off to a gas as it absorbs the air's latent heat energy.
- Compression: The refrigerant gas then passes into a compressor where the heat energy is increased.
- Heat Exchange: The refrigerant gas transfers through to a plate heat exchanger where the heat energy from the refrigerant is transferred to the wider heating system, causing the refrigerant to condense back to a liquid.
- Cycle Repeats: This process is then repeated to fulfil your heating demand.
Air source heat pumps are energy efficient, low carbon heating solutions which work effectively, even in cold climates.
We explain the process for how heat pumps work in more detail in the Education Area of our Knowledge Hub.
Heat pump efficiency explained
Air source heat pumps are highly efficient heating systems. For every kilowatt of electricity that a heat pump uses to operate, it produces more units of energy which can be used in the heating system, making them significantly more energy efficient than traditional systems.
Heat pump efficiency is commonly measured using two figures:
- COP (Coefficient of Performance): This measures a heat pump’s output of heat energy in relation to energy used at a particular time.
- SCOP (Seasonal Coefficient of Performance): This calculates a heat pump’s overall performance during a particular heating season, to give an average figure of energy produced compared to energy consumed.
The higher the COP or SCOP value, the more efficient the heat pump is.
Heat pumps work differently to traditional gas central heating systems – to help homeowners understand how to use and live with a heat pump, please watch our Living with a Heat Pump video series on our YouTube channel.
How does underfloor heating work?
Underfloor heating systems transfer the heat produced by the heat source (such as a heat pump) from the heating system into your rooms and living spaces through the floor. There are two main types of underfloor heating systems: electric and wet.
Types of Underfloor Heating Systems
- Electric Underfloor Heating (Electric UFH): These systems comprise of wires beneath the flooring which are connected to the mains electricity and when switched on, the wire heats up and this heat is then transferred into rooms.
- Wet Underfloor Heating (Wet UFH): This is the type of underfloor heating that Grant UK supply. Wet UFH systems feature a series of flexible pipes which are laid in your floor, through which hot water flows and heat is then radiated into your rooms.
Please visit our Education Area to learn more about how underfloor heating systems work.
Wet UFH System variants
There are different types of wet underfloor heating systems available to suit different flooring set-ups:
- Traditional screeded systems: The UFH pipework is laid within the construction of the floor floor with a thick layer of screed poured on top.
- Low profile UFH systems: The UFH pipework is typically fitted within adhesive panels on top of the floor construction, with a thin layer of screed poured on top.
- Non-screeded systems: These do not use screed at all, instead using heat emission plates or overlay boards into which the UFH pipework is secured.
Why choose underfloor heating?
Underfloor heating systems are effective heat emitters, using the entire floor as a surface area to evenly and consistently distribute warmth into a room, eliminating cold spots and draughts often associated with radiators. UFH is also an ideal partner for heat pumps, working efficiently at lower flow temperatures.
To learn more about how underfloor heating compares to radiators, or to explore different systems in more depth, please visit our Tips and Advice area or read through our Ultimate Guide to wet underfloor heating systems.
Compatibility: do ASHPs and UFH work well together?
Yes, air source heat pumps (ASHPs) and underfloor heating (UFH) are highly compatible and work incredibly well together.
Air source heat pumps work most efficiently when the temperature of their system water is typically between 35ºC-55ºC which is much lower than traditional boilers which have flow temperatures nearer to 70ºC. With a lower flow temperature, heat pump systems require a larger surface area to emit their heat and to achieve your desired room temperatures.
Underfloor heating provides the ideal solution, making the entire floor a surface area through which heat can be transferred from the heat pump system into a room and helping them to operate as efficiently as possible with optimal flow temperatures.
By pairing ASHPs with UFH, homeowners can enjoy:
- Improved energy efficiency
- Comfortable, even room temperatures
- Lowered carbon emissions
Underfloor heating is, therefore, one of the best heat emitters for low temperature heating systems like air source heat pumps.
What are the benefits of using UFH with a heat pump?
Installing underfloor heating (UFH) with a heat pump offers a range of benefits for your home, including:
- Highly efficient heating system
- Significantly lower carbon emissions
- No more gas bills
- Comfort from the floor upwards
- Seamless design and flexibility
Energy efficiency
Underfloor heating systems are designed to have low flow temperatures which make UFH the perfect match for air source heat pumps, maximising system efficiency and reducing energy consumption (compared to a traditional boiler).
Lower carbon emissions
By switching from a fossil fuel boiler to a heat pump and UFH, you can significantly reduce your home's carbon footprint, helping you to reduce your reliance on fossil fuels and achieve more sustainable living.
Eliminate fossil fuel bills
If you switch from a traditional gas boiler to a correctly designed heat pump system, you could eliminate your gas bill or fossil fuel energy bill.
Enhanced comfort
With UFH, heat is evenly distributed into a room from the floor upwards, creating a draught-free environment.
Seamless design & flexibility
With no need for radiators, an underfloor heating system offers more freedom with room layout and interior design, ideal for modern homes.
The combination of an ASHP with UFH can provide your home with high performance, low carbon heating with added comfort and design flexibility.
Is there anything I should consider before installing ASHP & UFH?
As with any new heating system, there are several factors that you and your installer will need to consider when planning the installation of an air source heat pump with underfloor heating for your home, including:
- System design and sizing
- Home insulation and heat retention
- Installation costs and timelines
- Planning permission and regulations
System design and sizing
It is essential that a heat pump system is correctly designed and specified to maximise performance, efficiency and long term reliability. To achieve this, your installer will need to:
- Carry out an accurate heat loss calculation
- Understand your household's heating and hot water demand
- Determine the correct heat pump heating output capacity
- Correctly size the heat emitters for the system, such as underfloor heating or radiators
Underfloor heating design matters too
When installing underfloor heating (UFH), thoroughly planning the pipework design is also crucial. Your installer must:
- Ensure sufficient pipework is laid out for the size of your room(s)
- Accurately map out the pipework layout
- Maintain appropriate spacing between the pipework for even heat distribution
Here at Grant UK, we have an in-house Design Team who can work with your installer to provide:
- System specification support
- Underfloor heating system designs and drawings
This can help ensure that your system is tailored to your home's needs for optimal efficiency and comfort.
Home insulation and heat retention
To support the efficient and effective operation of your heat pump, it is recommended to reduce heat loss throughout your home. Effective insulation can help maintain indoor temperatures and help the system to operate efficiently.
Key ways to minimise heat loss:
- Windows: Upgrading to double or triple glazing can reduce the amount of heat escaping through your windows.
- Roof: Appropriate loft insulation can reduce heat loss through your roof.
- Walls: Depending on your home's construction, cavity wall insulation or solid wall insulation is an energy efficiency measure which can reduce the heat escaping through your walls.
- Floors: With an UFH system, reducing heat loss in the floor is also recommended so when your installer lays the UFH, they will likely fit a membrane beneath the pipework which will reduce the amount of heat escaping downward or up the surrounding walls.
By insulating your home, you will help your air source heat pump (ASHP) and underfloor heating system to perform more effectively and efficiently.
We cover the topic of insulation and energy efficiency measures for homes in one of our other blogs – Getting your home heat pump ready.
Installation costs and timelines
Air source heat pump (ASHP) installations typically take longer to complete than traditional boiler installations. The installation timeframe will be determined by several factors, including:
- System upgrades: If additional works are needed elsewhere on your system, for example with upgrading pipework or heat emitters, this can extend the installation time.
- Energy efficiency improvements: If you are installing insulation or other energy saving measures, this can also increase the installation time.
- Property type: Installing a heat pump in a new build property will likely be quicker than a retrofit heat pump installation in an existing home.
With regard to installation costs, every installation will be different but the Energy Saving Trust estimates the average heat pump installation to cost approximately £14,000. We would recommend that you contact more than one installer to obtain a selection of quotations which are tailored to your home and requirements – find a local heat pump installer here.
Planning permission and regulations
In most instances, air source heat pump (ASHP) installations do not require planning permission because they will fall within the remits of permitted development. However, it is always worth checking with your Local Authority Planning Department prior to any work commencing in case there are specific restrictions for your property, especially if you home is:
- A listed building
- Located in a conservation area
- Situated in an Area of Outstanding Natural Beauty (AONB)
Installation standards & regulations
Every heat pump installation must comply with:
- The manufacturer’s installation instructions
- Current Building Regulations
- If you are also claiming Government funding (for example the Boiler Upgrade Scheme), the installation will also need to fulfil additional standards such as those set by MCS certification.
Checking these requirements early can help your installation to proceed smoothly to fulfil all legal and funding criteria.
Suitability: is a heat pump the right system for your home?
An air source heat pump heating system can suit many different types of homes, including:
- New build properties
- Flats
- Retrofit, existing homes both large and small.
Heat pumps can fulfil the space heating and hot water requirements for all sizes of homes provided the system has been thoroughly designed and accurately sized and specified.
Type of property
A new build is a blank canvas so it is ideally suited to have an underfloor heating system integrated during the early phases of the build and with current Building Regulations specifying high levels of insulation, they are ideally suited to a low temperature heat pump as well.
However, that does not mean that older properties cannot have a heat pump – far from it in fact. While some older homes may require additional energy efficiency measures to be fitted, heat pumps can be installed at properties of all ages. Read some of our case studies to some heat pumps in action:
- Grant Aerona³ heat pump upgrades the heating system of a sixteen year old farmhouse
- Hard to heat Oxfordshire home welcomes Aerona³ heat pump & QR Cylinder
- Grant Aerona³ heat pump is the right fit for barn conversion
Retrofitting into older homes
With retrofit heat pump installations, the main challenge you may face will be reducing the heat escaping from your home’s roof, windows and walls. In most instances, properties built after 1990 will already have suitable levels of insulation but your installer will talk through the energy efficiency improvements available so that you can decide what is right for your home.
When it comes to installing underfloor heating in a retrofit property, some householders may be put off by the prospect of having to dig up their floors in order to lay the UFH. The good news is that low profile underfloor heating systems are now available.
How does low profile UFH work
The Grant Uflex MINI UFH system is an example of a low profile underfloor heating system and it can be installed with minimal disruption to your home, as outlined below:
- Easy to install panels: The Uflex MINI system comprises of self-adhesive panels into which the underfloor pipework is clipped into place.
- Keep your existing floors: Provided your current flooring is level, these panels can be laid directly on top of an existing floor covering.
- Minimal changes to skirting or doors: A think layer of self-levelling screed is poured over the panels, meaning that your floor level will only increase by approximately 15mm so there may be little to no adjustment needed to your skirting or doors.
Climate and location
Air source heat pumps are designed to operate even in cold temperatures so if you live in a region which is colder than the average UK temperatures, a heat pump can still work for your home. Your installer will just consider a couple of additional factors when designing your system, such as cooler external air temperatures.
What if my home is not suitable?
If you home is not suited to a traditional screeded underfloor heating system, other options of heat emitter are available which will work well with an air source heat pump including:
If you and your installer decide that your home is not suitable for a heat pump alone, you could consider a hybrid heating system (which combines a heat pump with a traditional boiler).
What are the maintenance and running costs?
Air source heat pumps (ASHP) and underfloor heating systems (UFH) are simple to maintain and care for. With a heat pump, it is important to ensure that its air flow is unobstructed - some recommended heat pump maintenance tips include:
- Carry out quick visual checks of your heat pump on a regular basis
- Brush away any leaves which collect around your heat pump unit
- Do not lean garden furniture or bikes against your heat pump
If you are interesting in reading more about heat pump maintenance, we have a handy guide in our Knowledge Hub which shares five top tips for looking after a heat pump.
Annual heat pump servicing
In addition, it is recommended that you get your heat pump and underfloor heating system serviced annually. During an annual service, the heat pump servicing engineer will:
- Inspect the heat pump unit to check for any signs of damage
- Check the wider system to ensure it is operating as effectively as possible, supporting the long-term efficient operation of the heat pump.
Use our Find an Installer search to find local heat pump service engineers in your area or alternatively you can contact our ServicePlan Team. Through Grant UK’s ServicePlan, a heat pump service cost starts from £158.40 (correct April 2025).
Will using a heat pump with underfloor heating save me money?
An air source heat pump with underfloor heating should operate incredibly efficiently, producing more heat energy for each unit of electricity used compared to traditional boilers. However, with electricity costs currently being higher than some other fuel types, this will impact the cost of running a heat pump – to learn more about heat pump running costs, please visit the Energy Savings Trust website.
Paying for my new heat pump – what grants are available?
The average air source heat pump system will be more expensive to install than a conventional boiler replacement however, there are several funding schemes available which can provide financial support for new heat pump installations.
Government incentives and grants
Depending on where you are based in the UK, different Government incentives and initiatives are available, including:
- Boiler Upgrade Scheme: This is available to eligible households in England and Wales, offering a grant of up to £7,500 if you swap your fossil fuel boiler to an air source heat pump.
- Home Energy Scotland Scheme: This provides grants and loans to eligible households in Scotland, which also includes up to £7,500 grants for heat pumps.
- Zero rate VAT: Air source heat pumps installed in domestic properties throughout Great Britain are exempt from VAT.
Speak to your installer to discuss what funding you could be eligible for.
Trust Grant UK with your new heating system
Frequently Asked Questions
Q: Is an air source heat pump effective enough to heat my home in winter?
A: Yes, air source heat pumps (ASHPs) are designed to work efficiently even in cold UK winters. Modern ASHPs can extract heat from the air at temperatures below freezing. When paired with underfloor heating, which operates effectively at lower flow temperatures, the system provides consistent warmth throughout your home.
Q. How much does it cost to install an air source heat pump with underfloor heating?
A. The cost of installing an ASHP will vary between every installation due to different homes having different requirements. However, the Energy Savings Trust estimate that a typical air source heat pump installation can cost approximately £14,000. However, you may be eligible for financial support through Government funding such as the Boiler Upgrade Scheme (BUS), which provides grants of up to £7,500 for installing a heat pump to replace a traditional fossil fuel boiler.
Q. Can I install underfloor heating with an existing radiator system?
A. Yes, a new underfloor heating system can be integrated into an existing heating system where rooms use radiators, for example the UFH may be fitted downstairs and the existing radiators remain installed upstairs. Your installer will need to ensure that the system is adjusted and controlled appropriately for the mixed selection of heat emitters. Read more about the differences between underfloor heating and radiators here.