What does the Underfloor Heating Calculator do?

Compare water, electric mat and cable underfloor heating. See install costs and running costs vs radiators. All calculations are performed in your browser using official UK rates and thresholds.

Does this include waste allowance?

Yes. Most building material calculations include a standard 10% waste allowance. You can adjust this figure depending on the complexity of your project and cutting requirements.

Material prices are indicative estimates based on average UK prices. Actual costs vary by region, supplier, brand and current market conditions. Always get quotes from local suppliers.

Underfloor Heating Calculator

Compare water, electric mat and cable underfloor heating. See install costs and running costs vs radiators.

Last updated: April 2026 · Source: Energy Saving Trust — Underfloor heating

Floor Area (m²)

Hours/Day Heating

Install Cost

£525.00

Annual Running

£75.00

Monthly Running

£6.25

vs Radiators

Similar cost

Thin mats under tiles. Easy retrofit, ideal for bathrooms.

Disclaimer

This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.

How It Works

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.

Example: 25 m2 kitchen-diner, electric UFH

System type: Electric mat (200W/m2)
Materials: 25 x £55/m2 = £1,375
Installation: £500
Total cost: £1,875
Running cost: 5 kW x 6 hours/day x 24.5p x 180 days = £1,323/year
Radiator equivalent: ~£1,050/year (gas at current rates)
Electric UFH premium: ~£273/year (offset by even heat distribution)

Source: Energy Saving Trust — Underfloor heating

Frequently Asked Questions

What does the Underfloor Heating Calculator do?: Compare water, electric mat and cable underfloor heating. See install costs and running costs vs radiators. All calculations are performed in your browser using official UK rates and thresholds.
Does this include waste allowance?: Yes. Most building material calculations include a standard 10% waste allowance. You can adjust this figure depending on the complexity of your project and cutting requirements.
Are prices accurate?: Material prices are indicative estimates based on average UK prices. Actual costs vary by region, supplier, brand and current market conditions. Always get quotes from local suppliers.