Underfloor Heating Costs: Electric vs Wet (UK 2026)
Prices include supply and installation. New screed or floor build-up costs are additional for wet systems. London/South East: add 15-20%.
| System & Area | Electric (Dry) Cost | Wet (Water) Cost | Notes |
|---|---|---|---|
| Single bathroom (5-8 m²) | £400-£700 | £800-£1,600 | Electric most cost-effective for single rooms |
| Kitchen (15-20 m²) | £750-£1,700 | £1,800-£4,000 | Wet more efficient for larger areas |
| Open-plan ground floor (40 m²) | £2,000-£3,400 | £4,800-£8,000 | Wet better value and lower running costs |
| Whole house 3-bed (90 m²) | £4,500-£7,650 | £10,800-£18,000 | Wet system with manifold and controls |
| Whole house 4-bed (120 m²) | £6,000-£10,200 | £14,400-£24,000 | Screed/build-up costs add £3,000-£8,000 |
| Manifold and controls (wet, add) | - | £500-£1,500 | Per zone/room thermostat controls |
| New screed (wet system, add) | - | £20-£40/m² | Or low-profile overlay boards £15-£30/m² |
Running costs not included above. Electric UFH running costs are higher per kWh; wet UFH pairs well with heat pumps for lower running costs. Prices VAT-inclusive.
What Affects the Cost of Underfloor Heating?
- System type: electric mat or cable systems are cheaper to install but more expensive to run (direct electricity consumption). Wet (hydronic) systems cost more upfront but have lower running costs, especially with a heat pump.
- New build vs retrofit: new-build installation is significantly cheaper because pipes or mats are laid in the floor build-up before screeding. Retrofit means either raising floor levels (adding 50-150mm) or using low-profile overlay systems.
- Floor type: UFH works best under tiles and stone (low thermal resistance). Engineered timber and certain laminates are compatible if specified for UFH use. Thick carpet (tog rating above 1.5) significantly reduces efficiency.
- Area heated: cost per m² decreases for larger areas as manifold, controls and labour mobilisation are spread. Small rooms (under 5 m²) are expensive per m² due to fixed costs.
- Zoning and controls: a smart thermostatic zone controller per room adds £80-£250 per zone but significantly improves efficiency and comfort.
- Heat source: wet UFH is compatible with combi boilers, system boilers and heat pumps. It works optimally with heat pumps because it operates at lower flow temperatures (35-45 degrees C vs 60-70 degrees C for radiators).
- Screed or overlay: traditional liquid screed costs £20-£40/m² and takes 4-6 weeks to dry. Low-profile UFH overlay panels (20-30mm, no screed) are faster but reduce efficiency slightly.
- Insulation below: UFH should always have rigid insulation beneath (minimum 25mm, ideally 100mm on ground floors) to direct heat upward. Neglecting this wastes energy.
Electric Underfloor Heating: How It Works and When to Choose It
Electric UFH uses a resistive heating cable or mat laid in a self-levelling compound under tiles or directly under laminate. It is controlled by a programmable thermostat and runs on mains electricity. Installation is quick (1-2 days for a bathroom) and does not require a plumber or connection to the boiler circuit.
Electric UFH is best suited to: single rooms where the cost of wet pipework and a manifold would be disproportionate; bathrooms and en-suites where morning comfort is the primary goal; properties where wet UFH is impractical (e.g. flats without floor void); and properties with solar PV where cheap daytime electricity can offset running costs.
The main downside is running cost. At current UK electricity tariffs (around 24p/kWh in 2026), a bathroom heated for 2 hours per day will cost roughly £30-£60/year. Whole-house electric UFH as the primary heat source would be prohibitively expensive for most households.
Wet Underfloor Heating and Heat Pumps
Wet (hydronic) UFH circulates warm water through a network of plastic pipes (typically PEX or PERT) embedded in screed or routed through overlay panels. A manifold distributes water to each zone, and individual zone valves controlled by room thermostats regulate temperature.
Wet UFH operates most efficiently at flow temperatures of 35-45 degrees C, which is precisely the range at which air-source and ground-source heat pumps are most efficient. This makes wet UFH and heat pumps an ideal combination — the Boiler Upgrade Scheme (£7,500 government grant for air-source heat pumps) makes this combination even more financially attractive in 2026.
Wet UFH can also run from a combi or system boiler, though at higher flow temperatures the efficiency advantage over radiators is reduced. A well-designed wet UFH system in a well-insulated home (EPC C or above) can reduce heating bills by 10-20% compared to a conventional radiator system running from the same heat source.
Insulation Is Essential for Efficiency
Underfloor heating without adequate insulation below the floor slab wastes a substantial proportion of heat into the ground rather than upward into the room. On ground floors, a minimum 25mm rigid insulation board (ideally 100mm Celotex or equivalent) must be installed beneath the screed or pipes. Skipping this step — common with budget installers — dramatically increases running costs and defeats the purpose of UFH.
Plan Your Heating System Before You Buy
Our planner helps you set a realistic refurbishment reserve before you buy — so you can budget for underfloor heating, heat pump compatibility and insulation upgrades as a joined-up package rather than piecemeal decisions after completion.