Underfloor Heating and Heat Pumps

If you are weighing up a heat pump for your UK home, one question comes up again and again: does the heating system you already have — or the one you plan to install — suit a heat pump? Underfloor heating (UFH) is the answer most heat pump engineers reach for first, and for good reason. The two technologies are so well matched that combining them can push seasonal efficiency well above what a typical radiator system achieves. This guide explains why, and what it means in practice for retrofit and new-build homeowners.

Why heat pumps and underfloor heating are such a good match

Heat pumps are most efficient when they operate at low flow temperatures — the temperature of water circulating through the heating emitters. A conventional gas boiler is designed to push water at 60–70°C around standard radiators. Heat pumps work best between 35 and 50°C, and efficiency falls materially as flow temperature rises: every additional 5°C costs roughly 10–15% of seasonal performance.

Underfloor heating runs at exactly the temperatures that suit a heat pump. Because UFH spreads heat across a large floor surface area rather than concentrating it in a small radiator panel, it can warm a room effectively at just 35–45°C. That alignment between the emitter's natural operating range and the heat pump's efficiency sweet spot is the core reason the combination works so well.

The practical result is a meaningful improvement in the Seasonal Coefficient of Performance (SCOP) — the real-world measure of how many kilowatt-hours of heat a system delivers per kilowatt-hour of electricity consumed. The Energy Saving Trust's heat pump field trial, published on GOV.UK, found that air source heat pumps across the Phase I dataset averaged a seasonal performance factor of around 2.45. Systems running at lower flow temperatures — as UFH enables — can push that figure toward 3.5–4.5, which directly cuts running costs. For a full breakdown of how flow temperature drives SCOP and what that means for your bills, see our heat pump running costs guide.

Wet (hydronic) UFH vs electric UFH: which connects to a heat pump?

Only wet (hydronic) underfloor heating connects to a heat pump. Wet UFH circulates warm water through a network of pipes embedded in or clipped beneath the floor — exactly like a conventional radiator circuit, but spread across the floor. The heat pump heats the water in the same way it would feed radiators, and the manifold distributes it around the UFH loops.

Electric UFH — heating mats or cables under tiles or timber — runs on direct electrical resistance and has no water circuit. It cannot be connected to a heat pump at all. Electric UFH is useful in small areas (a bathroom, a kitchen extension) and can work well on solar-generated electricity, but it plays no role in a whole-home heat pump heating system.

When people talk about heat pump underfloor heating in a UK context, they mean wet hydronic UFH throughout the home, fed by the heat pump's water circuit.

Retrofitting underfloor heating with a heat pump

Retrofitting wet UFH into an existing home is possible, but it is disruptive and the cost varies significantly depending on the floor construction. The most thorough approach — embedding pipes in a new liquid screed or concrete slab — requires lifting all existing floor finishes, laying insulation, running the pipe grid, pouring screed, and waiting several weeks for it to cure before fitting new floor coverings. In a lived-in home, that means significant disruption to each room in turn.

Less invasive options do exist. Low-profile overlay systems use thin aluminium spreader plates and a slimmer pipe (typically 10–12 mm), routed in pre-routed boards that add only 15–25 mm to floor height. These are increasingly popular in retrofit projects because they avoid screed entirely, though they are more expensive per square metre than screed-based systems and need careful management of door and threshold heights.

A third option, particularly under suspended timber floors, is clipping pipes to the underside of the floor and fitting insulation below. This is less disruptive than screed but can be difficult to access and delivers slightly lower heat output per square metre because the floor covering above acts as an insulator.

For homeowners where full UFH retrofit is not practical, oversized low-temperature radiators are the recommended alternative. A radiator sized for 35–45°C operation (roughly twice the panel area of a standard radiator for the same room heat output) can achieve similar SCOP benefits to UFH. They are easier and cheaper to fit room-by-room than a full UFH system.

New builds: the natural pairing

In a new build, combining a heat pump with underfloor heating is straightforward. The UFH pipe network is laid across the slab or on the ground floor insulation before the screed is poured — a standard part of the construction sequence that adds modest cost compared to the disruption of retrofitting. Upper floors can be served by either UFH in a floating screed or, more commonly, by low-temperature radiators.

The Future Homes Standard, being implemented for new homes in England from 2025, requires new builds to be “future-proofed for net zero” with low-carbon heating. In practice, most new homes built to this standard will use a heat pump as the primary heat source, and UFH on the ground floor is the natural emitter choice given the flow temperatures involved. Developers and self-builders planning compliant homes should design both together from the start rather than treating them as separate decisions.

Ground source heat pumps pair especially naturally with new-build UFH because GSHPs operate at even lower flow temperatures than air source — SCOP 3.5–4.5 is typical — and the ground collector can be specified at the same time as the foundation and groundworks. For detail on ground source systems, see our ground source heat pump guide.

Heat pump brands and low-temperature performance

Leading heat pump manufacturers have designed their systems specifically for low-temperature operation. Brands such as NIBE, Vaillant, Mitsubishi Electric, and Daikin all offer air source and ground source models with rated COPs at 35°C flow temperature published on their product data sheets. When specifying a heat pump for a UFH system, ask your MCS-certified installer to confirm the unit's rated performance at 35°C rather than relying solely on the headline A7W55 rating (which uses a 55°C flow temperature standard). The difference between a system optimised for low-temperature emitters and a standard unit running at higher flow temperatures can be several tenths of a SCOP point — meaningful over a full heating season.

Running costs: the efficiency gain in numbers

Lower flow temperature means lower running costs. At Ofgem's Q2 2026 price cap (electricity 24.67p/kWh), a heat pump running at SCOP 3.5 — typical for a well-installed UFH system — costs roughly £810 per year to heat a three-bedroom semi with 11,500 kWh annual heat demand. The same home on a SCOP 2.5 system (standard radiators, higher flow temperature) would cost around £1,135 per year — a difference of over £300 annually. That gap widens as the system ages and as electricity prices change relative to gas.

Coupling the efficiency gain with a Boiler Upgrade Scheme (BUS) grant — currently £7,500 for air or ground source heat pumps in England and Wales, administered by Ofgem — improves the overall financial case. Your MCS-certified installer applies on your behalf. For a full assessment of whether a heat pump makes financial sense for your home, see our are heat pumps worth it guide.

Summary: when does UFH make sense with a heat pump?

Underfloor heating makes most sense alongside a heat pump in three situations: a new build where the UFH can be integrated into the construction programme at low marginal cost; a substantial renovation where floors are already being lifted for other reasons; or a home where the efficiency gains justify the retrofit disruption — typically a large, well-insulated property where the owner plans to stay long-term. In all other cases, specifying oversized low-temperature radiators achieves most of the efficiency benefit at a fraction of the disruption.