Underfloor heating and heat pumps are a natural match — both run at low flow temperatures. Here’s what to know about costs, retrofit feasibility, and floor compatibility in UK homes.
Underfloor heating and heat pumps are genuinely well-matched — a combination that’s more than marketing language. Heat pumps run most efficiently at low flow temperatures (35–45°C), and underfloor heating is designed to work at exactly those temperatures. Together, they can achieve a seasonal CoP well above what either delivers with a conventional radiator system or a gas boiler. This guide explains why they work together so well, what it costs to combine them in a UK home, and the practical challenges of retrofitting underfloor heating into an existing property.
Why heat pumps and underfloor heating work so well together
A standard gas boiler heats water to 70–80°C before circulating it through your radiators. That high temperature means radiators can be relatively small and still push enough heat into a room. Heat pumps work differently — they’re at their most efficient at low flow temperatures. Every 5°C drop in flow temperature improves efficiency by roughly 10%. Run a heat pump at 35°C instead of 55°C and you’re looking at roughly a 40% efficiency gain.
Underfloor heating (UFH) is designed to run at 30–45°C. Because the entire floor surface radiates heat, the lower temperature is enough to warm a room comfortably. This makes UFH the ideal emitter system for a heat pump — you get the maximum efficiency from the pump, and the floor provides gentle, even warmth with no cold spots.
Nesta’s heat pump field trial found that heat pumps connected to underfloor heating systems achieved notably higher seasonal performance factors than those connected to radiator-only systems — in some cases 20–30% higher efficiency. Over the life of the system, that difference adds up to hundreds of pounds in savings.
Wet underfloor heating vs electric underfloor heating
There are two types of underfloor heating, and only one works meaningfully with a heat pump:
| Type | How it works | Compatible with heat pump? | Best for |
|---|---|---|---|
| Wet (hydronic) UFH | Warm water circulated through pipes embedded in floor | Yes — ideal combination | Whole-house heating systems |
| Electric UFH | Electric heating cables or mats under tiles | No (it’s a separate system) | Small areas, bathroom floors, supplementary warmth |
Wet underfloor heating is what integrates with a heat pump. Electric UFH runs on direct electricity and isn’t connected to the central heating circuit — it doesn’t benefit from a heat pump’s efficiency. Electric UFH can be a useful addition to a bathroom or kitchen for comfort, but it shouldn’t be confused with a whole-house heat pump system.
New build vs retrofit: the key difference
In a new build, wet underfloor heating is straightforward — pipes are laid in the screed before the floor finish goes down. Costs are relatively low (£60–£100 per m² installed) and the whole system can be designed from scratch to work with a heat pump at optimal flow temperatures.
Retrofitting UFH into an existing property is more challenging — and more expensive:
Screed-based retrofit (traditional)
Existing floors are dug up, pipes are laid, and new screed is poured. This is the most disruptive option — rooms are out of action during the process. However, it provides the most thermally efficient result. Cost: roughly £80–£150 per m² installed.
Low-profile overlay systems
A range of ultra-thin panel systems sit on top of existing floors and raise floor height by only 15–30mm. Brands like Warmup and Polypipe produce overlay boards with routed grooves for pipes. These are far less disruptive but have slightly lower heat output than screed-embedded systems. Cost: £80–£130 per m². They work best with timber or laminate floor coverings rather than heavy tile.
Suspended floor (joist) installation
In homes with suspended timber floors (common in pre-1960s UK properties), pipes can be installed between joists from underneath — either from a basement or crawl space, or by lifting floorboards. This avoids raising floor height but requires good access. Thermal efficiency is lower than screed unless good insulation is fitted between joists. Cost: £70–£120 per m².
Cost of wet underfloor heating with a heat pump
For a 3-bedroom semi-detached home (approximately 90m² of floor space), here’s a rough budget for a full wet UFH + ASHP system:
| Component | Estimated cost |
|---|---|
| Air source heat pump (installed) | £8,000 – £14,000 |
| Wet UFH (retrofit overlay, 90m²) | £7,200 – £11,700 |
| Hot water cylinder | £600 – £1,200 |
| Controls and manifold | £500 – £1,000 |
| Total (before grant) | £16,300 – £27,900 |
| BUS grant deduction | -£7,500 |
| Net total | £8,800 – £20,400 |
These figures assume a complete retrofit. If UFH is only installed on the ground floor (which is common — radiators are often retained upstairs), costs are roughly halved. See our heat pump costs guide for a breakdown of the heat pump portion alone.
Which floor coverings work with underfloor heating?
Not all floor coverings conduct heat well. The ideal floor finish for UFH with a heat pump is one that transfers heat efficiently and doesn’t insulate the room from it:
| Floor type | UFH compatibility | Notes |
|---|---|---|
| Porcelain or ceramic tile | Excellent | Best heat transfer, ideal choice |
| Natural stone | Excellent | Very good conductor, heavy |
| Engineered wood | Good | Check manufacturer’s UFH rating; max 27°C floor temp |
| Laminate | Good | Low tog rating required (<0.1 m²K/W) |
| Solid hardwood | Poor | Prone to movement with temperature changes |
| Thick carpet | Poor | High tog rating insulates against heat output |
If you’re planning UFH in a room with an existing solid hardwood floor, seek specialist advice — the floor may need to be replaced or the UFH run at very controlled temperatures to prevent warping.
Is underfloor heating worth adding if you’re getting a heat pump anyway?
The answer depends on where you’re starting from. If you have a new build or are doing a major renovation, wet UFH is almost always worth specifying — the additional cost at that stage is modest and the efficiency and comfort gains are significant. If you’re retrofitting a heat pump into an existing home with good radiators, the economics are less clear: you’d be adding £7,000–£12,000 to achieve efficiency gains that might save you £150–£250/year in running costs. A 40–80 year payback is not compelling.
A practical middle ground for retrofit homes: install UFH on the ground floor (where screed or overlay systems are easiest) and upgrade radiators upstairs. The ground floor benefits from the high efficiency of low-temperature UFH, while upstairs radiators run slightly warmer. This hybrid approach is becoming increasingly common and is well-supported by heat pump manufacturers’ zoning controls.
The Energy Saving Trust recommends getting a heat pump designed around your chosen emitter system — not bolted onto an existing setup. Discuss UFH plans with your installer during the heat loss survey stage, before system design is finalised. Read more about the full installation process in our heat pump installation guide, and use our savings calculator to model the efficiency gains.