Air Source Heat Pump Underfloor Heating: A Comprehensive Guide

When you combine underfloor heating with air source heat pumps (ASHPs), you create a highly efficient system that delivers steady, low-cost warmth throughout your home. With typical UK household energy bills still 43% higher than winter 2021/2022 levels (House of Commons Library), improving your home’s efficiency is a smart and practical necessity.

In this guide, we explain how underfloor heating with heat pumps works, what it costs, and what to consider before arranging your air source heat pump installation.

If you’re planning a new build, upgrading your heating system, or improving your home’s insulation, getting the right advice early on can make a big difference.

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When an underfloor heating system connects to an air source heat pump, it uses low-temperature water to warm your home steadily and efficiently. The heating system runs on the ground floor, heating from beneath the surface, often lifting the floor or making space for pipework.

Let’s break down how the full process works:

The system goes through 4 stages to produce heating:

Stage 1: Heat extraction

With an air source heat pump installed outside your home on a wall or a solid base (such as a concrete pad), the system pulls in air from outside. Even in temperatures as low as  -15 °C, modern ASHPs can still extract usable heat, as confirmed by iHeat, which notes they operate efficiently in sub-zero conditions. 

Fans pull outside air across the evaporator coil, where the refrigerant absorbs heat and turns into a gas.

Stage 2: Heat compression

After the refrigerant absorbs heat from the air, it flows into the compressor inside the outdoor unit. This process squeezes the refrigerant, increasing its pressure and temperature to create usable warmth. For underfloor heating, the ideal flow temperature is between 40o C and 45 o C, a range recommended by UK underfloor specialist Nu-Heat for maintaining comfort and energy savings.

Stage 3: Warming the water and floor

Once compressed, the hot refrigerant enters a heat exchanger. Here, its heat is transferred to water, raising the water temperature, typically to 35^oC - 45^oC. This level is ideal for wet underfloor heating systems. This system uses warm water pumped through pipes beneath the floor, unlike electric systems that rely on heating cables.

This warm water is then pumped through pipes laid beneath your floor, gently heating the surface. The heat rises evenly upwards from wherever the pipes run, maintaining safe floor temperatures between 25 o C and 28 °C, as recommended by British Standard EN 1264. 

Installing underfloor heating with an air source heat pump system costs £12,000 to £22,000 for a standard 3-4 bedroom UK home (around 90- 110m²). This includes the heat pump system, wet underfloor system for the ground floor, basic floor prep, and professional installation.

Typical total installation cost: £12,000 - £22,000

This includes:

Extra costs to consider:

Regional factors can affect pricing. For example, installing heat pumps in Scotland or heat pumps in Wales may require system adjustments to suit colder climates or local regulations.

To gauge what it would cost for your UK home, it’s best to get an accurate heat pump quote based on your property size, current heating system, floor construction, and energy needs.

Use our quick 30-second form below to get matched with up to 4 qualified heat pump installers who understand your property type and heating needs.

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No, underfloor heating with an air source heat pump doesn’t suit every household. Your property must meet certain conditions for the system to be a practical choice.

If your home fits more into the second group, consider upgrading your insulation as a first step. You can also compare ground source heat pumps, which may be more suitable for certain properties.

The best choice for underfloor heating is a low-temperature air to water heat pump. Top models include the Vaillant aroTHERM Plus, Samsung EHS Mono, and Mitsubishi Ecodan.

These systems provide steady heat at flow temperatures between 35°C and 45°C, which matches how wet underfloor heating systems distribute warmth.

When choosing your system, it’s important to consider the heat pump size, especially if you’re heating multiple floors or larger homes.

Here are three top-rated air source heat pumps for underfloor heating available in the UK: 

This quiet, MCS-certified system operates at around 54 dB (A) and uses the natural refrigerant R290 for greater efficiency. It can achieve flow temperatures of up to 70°C, making it a suitable high temperature heat pump for homes that need higher heat output. It’s also ideal for well-insulated homes up to 150 m2 with underfloor heating.It's especially popular in retrofitted homes where radiators remain, and works efficiently with both underfloor and traditional systems. Vaillant confirms that the aroTHERM Plus is "ideal for use with underfloor heating, radiators and fan coils," making it suitable for both new builds and retrofit installations.

The Samsung EHS Mono works in temperatures from -25 °C to +35 °C, which is ideal for the UK’s variable climate. Its Seasonal Coefficient of Performance (SCOP) is around 4.5, which means it produces roughly 4.5 units of heat for every unit of electricity it uses, measured across a full heating season.It’s compact, all-in-one outdoor unit stands at around 1 metre tall, making it suitable for homes with limited external space.It can comfortably heat properties with a floor area of around 120m2 to 140m2, depending on how well the home is insulated. 

A flexible, quiet model that supports homes ranging from  90 m² to over 200 m², depending on insulation. All models are MCS certified and can be equipped with an integrated heat pump water heater, providing a combined hot water supply and heating system.

Installing an underfloor heating system with a heat pump can lower your energy bill by up to 25 - 40% compared to a standard gas boiler. It also frees up space by removing bulky radiators and spreads gentle, even warmth throughout each room. 

According to the Energy Saving Trust, switching from an old G-rated gas boiler to a heat pump can save around £290, with even more savings if you’re replacing electric heating.

These benefits make heat pump underfloor heating one of the most efficient and comfortable options in modern UK homes.

The main drawbacks of heat pump underfloor heating include higher installation cost, disruption during installation, and slower heat-up time compared to radiators. 

Yes. It’s a good fit if your home is well-insulated, and you’re renovating. 

No. It’s less suitable if your home loses heat easily or you can’t make changes to your floors. 

Underfloor heating with a heat pump works best in homes that hold in warmth. Good insulation helps stop heat from escaping through walls, floors or windows. 

That’s because heat pumps warm your home using water (at 35 to 55^o C,  best for underfloor heating), which is lower than 70 - 80^oC temperatures used by traditional boilers. Lower temperatures use less energy, but only work well if your home can retain the heat.

But to keep your home warm with that lower heat, the warmth must stay inside. That’s why insulation plays such an important role.

If your home meets these conditions, the next step is to look at costs and see if any financial support is available. 

To help with that, you can use our free quote service instead of spending hours researching companies that install both underfloor heating and air source heat pumps.

Use our 30-second form to get matched with up to 4 qualified heat pump specialists and compare quotes, completely free.