Underfloor Heating with a Heat Pump: The Complete UK Guide for 2026

Why Heat Pumps Love Underfloor Heating

Heat pumps operate most efficiently at low flow temperatures — ideally 35–45°C. At these temperatures a modern air source heat pump achieves a COP (coefficient of performance) of 3.5–4.0, meaning it delivers 3.5–4 kWh of heat per 1 kWh of electricity consumed. Underfloor heating typically runs at exactly these temperatures, making UFH the natural partner for a heat pump.

By contrast, traditional radiators require flow temperatures of 55–75°C to heat a room effectively. Running a heat pump at 70°C to supply conventional radiators drops its COP to 2.0–2.5. Every 5°C reduction in flow temperature improves COP by 0.3–0.4 — so switching from 70°C radiators to 40°C UFH can cut heating running costs by 30–40%.

Wet UFH vs Electric UFH — Which Is Right?

Wet underfloor heating uses warm water circulated through pipework embedded in the floor. It is the preferred choice when paired with a heat pump because it can use the heat pump's hot water output directly. Wet UFH costs £70–£100/m² for new-build or £95–£190/m² for retrofit (screed-in or overlay system).

Electric UFH uses resistance cables or heating mats under floor tiles. It is cheaper to install (£30–£80/m²) but expensive to run — electricity at 24p/kWh versus gas at 6p/kWh makes it typically 4× more expensive than wet UFH with a heat pump. Electric UFH works well in small wet rooms where a wet system is impractical, but it should not be used as the primary heating system.

Costs for a Whole-House Wet UFH System

For a 3-bedroom semi-detached house (approx. 90 m²), a wet UFH system with a heat pump typically costs: screed-based new-install £8,500–£13,500 for UFH alone, plus £8,000–£15,000 net for the heat pump (after £7,500 BUS grant). The combined system for a mid-size home therefore costs £17,000–£28,000 before any further grants. ECO4 can contribute significantly for eligible households, and Warm Homes Local Grant (from 2027) covers up to £15,000.

Retrofit UFH: Is It Possible Without Digging Up the Floor?

Yes — overlay systems allow UFH to be installed without removing the existing floor. Thin plastic plates clip the UFH pipe into a low-profile (18–25 mm) panel that sits directly on the existing screed or floorboards. The floor covering (tiles, LVT, engineered wood) is then laid directly on top. The slight height increase (18–25 mm) requires door trimming and can be managed at thresholds.

Overlay systems cost more per m² than screeded-in systems but save the labour cost and disruption of breaking out floors. They are widely used in East Anglia heritage properties where solid floors are sensitive.