Heat Pump Underfloor Heating: Does It Work? UK Guideoom House UK (2026)

Why does underfloor heating suit a heat pump?

The key is surface area.

A radiator releases heat from a relatively small panel. Underfloor heating uses much of the floor as the heat emitter, so the water can be cooler while still delivering enough heat into the room.

That matters because a heat pump must raise low-temperature heat from outside to a useful temperature inside. Generally, the higher the required heating-water temperature, the harder the compressor has to work.

Energy Saving Trust’s installer guidance demonstrates this relationship: heat-pump efficiency normally improves as the required leaving-water temperature falls.

For the complete evaporator, refrigerant, compressor, condenser and expansion-valve process, read Getfreequote.co.uk’s guide to how air source heat pumps work rather than repeating the whole refrigeration cycle here.

For underfloor heating, the important point is simple: a larger heat-emitting surface can reduce the water temperature the heat pump needs to produce.

What flow temperature does underfloor heating use with a heat pump?

There is no single correct temperature for every property.

Many heat-pump UFH systems operate at roughly 30–40°C, but the actual design temperature depends on:

• the calculated room heat loss;
• pipe spacing;
• heated floor area;
• insulation;
• floor construction;
• floor covering;
• outdoor design temperature.

Daikin’s heat pump and underfloor heating guidance describes typical underfloor leaving-water temperatures of around 25–35°C. Energy Saving Trust, meanwhile, says heat pumps often supply radiators at around 35–45°C.

The aim is not simply to chase the lowest number possible.

Instead, the system should use the lowest practical flow temperature that can still keep every room warm during the property’s design winter conditions.

For a deeper explanation, see Getfreequote.co.uk’s guide to air source heat pump temperature.

Wet vs electric underfloor heating

Wet UFH contains water-filled pipes beneath the floor. A heat pump can heat this water, allowing the heat pump and UFH to operate as one integrated heating system.

Electric UFH contains resistance cables or mats. Electricity flows through them and produces heat directly.

Therefore, adding a heat pump does not convert existing electric UFH into heat-pump underfloor heating.

Electric UFH can still be practical for a bathroom or another small area used for short periods. However, Energy Saving Trust notes that electric underfloor heating can become expensive when used for larger spaces or long periods compared with wet systems using efficient heat sources.

Can existing underfloor heating work with a heat pump?

Often, yes. But it should be checked rather than assumed.

The designer needs to confirm that each room can produce enough heat at the proposed lower water temperature.

They should assess the room heat loss, pipe spacing, loop lengths, manifold flow rates, insulation and floor-covering resistance.

Older wet UFH may also have been designed around a boiler and blending valve. The blending valve reduces hotter boiler water to a temperature suitable for the floor.

With a low-temperature heat source, the arrangement may need changing. Heat-pump-specific UFH systems can supply water without a conventional blending valve because the heat source itself already produces low-temperature water.

A proper heat pump survey should assess the underfloor heating alongside heat-pump capacity, pipework, hot-water requirements and electrical supply.

Can you combine underfloor heating and radiators?

Yes.

Underfloor heating downstairs with radiators upstairs is a common and practical retrofit arrangement.

Energy Saving Trust specifically notes that homeowners may use UFH downstairs and radiators upstairs, reducing the cost and disruption involved in installing underfloor heating throughout the property.

The important issue is radiator sizing.

Upstairs radiators need enough surface area to produce the required room heat at the chosen low water temperature. Some existing radiators may already be large enough. Others may need larger, double-panel or triple-panel replacements.

So the real design question is not simply “underfloor heating or radiators?”

It is:

Can every room receive enough heat at an efficient system flow temperature?

Floor construction, insulation and coverings matter

UFH performance depends heavily on what surrounds the heating pipes.

Screeded concrete floors can distribute heat evenly but usually respond relatively slowly.

Suspended timber floors can also work with UFH. Depending on the system, they may use insulation together with aluminium heat-spreader plates or purpose-designed panels. Low-profile overlay systems provide another option where removing the existing floor would create excessive disruption.

Insulation underneath the heating layer is important because the objective is to direct useful heat upwards into the room rather than down towards the ground or an unheated void.

Floor finishes matter as well.

Tile and stone transfer heat readily. Carpet can also work, but thick carpet and underlay restrict heat transfer. Energy Saving Trust cites a combined carpet-and-underlay recommendation of 2.5 tog or less for faster heat transfer.

Older and listed properties require additional care. Historic England’s guidance on installing heat pumps in historic buildings notes that changes to floors, doors, steps and skirtings may have conservation implications.

Is heat pump underfloor heating better for new builds or retrofits?

UFH is easiest to integrate during a new build, extension or major renovation.

The designer can coordinate insulation, pipework, screed and finished floor height before construction starts.

Retrofit is still possible. Options include low-profile overlay systems, routed or milled systems and between-joist solutions for suspended timber floors.

The right method depends on available floor height, door thresholds, stairs, insulation and the existing structure.

If you already intend to replace a kitchen or ground-floor finish, that can be a logical opportunity to install wet UFH.

Before committing, check whether your home is suitable for a heat pump as a complete heating system rather than assessing the floor alone.

Will underfloor heating reduce heat-pump running costs?

Potentially, but there is no responsible fixed saving percentage.

Lower flow temperatures can improve heat-pump efficiency. That may reduce the electricity needed to deliver the same amount of useful heat.

However, actual bills still depend on:

• property heat demand;
• seasonal heat-pump performance;
• electricity tariff;
• hot-water demand;
• heating controls;
• the system being replaced.

Underfloor heating can also respond more slowly than radiators, particularly when pipes are buried in a high-mass screed.

Heat pumps generally suit steady operation rather than repeatedly allowing the building to become cold and then demanding a rapid temperature increase. Energy Saving Trust recommends continuous operation with sensible temperature setbacks rather than treating a heat pump exactly like a traditional boiler.

Do not replace perfectly suitable radiators purely because someone promises a guaranteed UFH payback.

If existing or upgraded radiators can already heat the rooms at a low design temperature, installing UFH may not justify the building work.

What does heat pump underfloor heating cost?

Underfloor heating costs vary significantly by project.

Energy Saving Trust currently cites an indicative installed cost of around £85–£110 per square metre for wet UFH, based on Checkatrade figures. Treat this as a broad guide rather than a quotation.

Costs can increase where installation requires floor removal, new insulation, screed, joist work, door changes or new floor finishes.

For the heat pump itself, eligible homes in England and Wales can currently receive £7,500 towards an air-to-water or ground-source heat pump through the Boiler Upgrade Scheme.

Until 31 March 2027, qualifying off-gas properties replacing oil or LPG can receive £9,000 towards an eligible air-to-water or ground-source system. GOV.UK and Ofgem confirm the current grant levels.

For the detailed rules, see Getfreequote.co.uk’s Boiler Upgrade Scheme 2026 updates.

Do not assume the headline grant will automatically cover every separate flooring or renovation expense.

How to design heat pump underfloor heating properly

1. Calculate room-by-room heat loss. The heating emitter needs enough output to meet each room’s requirement. The MCS heat-load methodology is based on room-level calculations.
2. Choose the design flow temperature. Aim for the lowest practical temperature that still satisfies the calculated heat demand.
3. Check UFH output. Pipe spacing, usable heated area, insulation and floor finish all change the result.
4. Coordinate radiators. Where radiators remain upstairs, size them around the same low-temperature strategy where practical.
5. Review manifolds and controls. Boiler-era pumps or blending arrangements should not automatically be retained.
6. Check finished floor levels. Doors, stairs, fitted kitchens and thresholds can turn a straightforward UFH installation into a larger building project.