Underfloor Heating Calculator

Underfloor heating (UFH) distributes heat evenly across a room from beneath the floor surface. There are two main types: wet systems (warm water piped through the floor, connected to a boiler or heat pump) and electric systems (heating cables or mats beneath the floor). Wet systems are more efficient for whole-house heating, while electric systems are better for individual rooms.

Installation costs vary significantly. Electric UFH costs £50-£80 per square metre for materials plus installation, making it affordable for bathrooms and kitchens. Wet UFH costs £100-£200 per square metre installed and is best fitted during new builds or major renovations when the floor is being replaced anyway.

Running costs depend on insulation, floor covering and heat source. UFH operates at lower water temperatures (35-45 C vs 60-80 C for radiators), making it particularly efficient when paired with a heat pump. This calculator estimates installation and running costs for your room or whole-house setup and compares them against traditional radiator systems.

UK underfloor heating types 2026. Wet (hydronic): heated water flows through pipes — best for new builds + extensions. £80-£120/m² installed. Electric (mat): for retrofits, bathrooms, individual rooms. £40-£80/m² installed. Loose wire (electric): for irregular shapes. Higher upfront cost than mat, lower per m². Hot air systems: rare in UK (more common Scandinavia, US). Sweat-proof bathroom underfloor: most common UK retrofit application.

Running costs UK 2026. Wet underfloor with heat pump: 50-70% cheaper than gas boiler underfloor — large boiler saving. Wet with gas boiler: similar to standard radiator system but more comfortable. Electric underfloor: 28p/kWh × typical 100W/m² × 4 hours/day = £4/day for 30 m² room. Electric expensive for whole-house heating; cheap for bathroom-only (200W × 1 hour daily = £0.06/day). Best efficiency: wet underfloor with heat pump in well-insulated home.

Installation costs. Wet underfloor 100 m² (whole bungalow): £8,000-£14,000 fitted (pipes + manifold + screed). Adding to extension: £4,000-£8,000 typical 25 m² extension. Retrofit existing house: needs 50-65mm screed thickness + insulation = floor levels rise by 80-100mm. Often impractical retrofit (door clearance, stairs). Electric mat retrofit bathroom: £400-£900 fitted (5-10 m²). Boiler/heat pump output sizing: matches UFH heat output 50-100 W/m².

Best UK floor coverings for underfloor. Best: tile/stone — high thermal conductivity, even heat distribution. Engineered wood: works well, designed for UFH stability. LVT (Luxury Vinyl Tile): excellent conductivity + comfort. Carpet: WORST — insulating layer reduces output 30-50%. Solid wood: not ideal — expansion/contraction issues. Laminate: usable but needs UFH-rated underlay. Always check floor manufacturer's UFH compatibility before installing.

Building Regs and warranties. Building Regulations Part L: insulation levels must support UFH efficiency. Minimum 50mm insulation under wet UFH typical. Manifold + zone controls: each room independent thermostat for efficiency. NHBC + LABC warranties: wet UFH requires pressure test certificate. Manufacturer warranty: typically 10 years on pipes; 5 years on controls. Specialist installer accreditation: NICEIC (electric) or APHC (plumbing) — choose certified installer to maintain warranty.