Heat pump cost calculator
Compare the running cost of your current heating with a heat pump and see how long the installation could take to pay back.
Your estimate
Annual running-cost saving
£7.03
- Current heating cost per year
- £757
- Heat pump running cost per year
- £750
- Heat delivered per year
- 8,550 kWh
- Heat pump electricity use
- 2,850 kWh
- Cost after grants
- £12,000
- Simple payback
- 1,707 years
Estimates for planning only — not a quote, survey or financial advice.
Sources for the pre-filled values — United Kingdom
- Ofgem — Energy price cap unit rates (Great Britain average, Direct Debit) · 1 October – 31 December 2026 · accessed 2026-11-06 · Unit rates only; daily standing charges are not included.
- Ofgem — Typical domestic consumption values (medium), from 1 July 2026 · 2026 TDCV · accessed 2026-11-06
How this is calculated
Formula
- Heat delivered = fuel used × current efficiency
- Heat pump electricity = heat delivered ÷ SCOP
- Annual saving = current fuel cost − heat pump electricity cost
- Payback = (installation cost − grants) ÷ annual saving
Assumptions
- Enter fuel use in kWh: 1 US therm ≈ 29.3 kWh, 1 litre of heating oil ≈ 10 kWh, 1 m³ of natural gas ≈ 10–11 kWh (check your bill).
- SCOP depends on the model, the flow temperature and the climate; well-designed systems with low flow temperatures do better.
- Standing charges, servicing and the cost of replacing your existing boiler are not included.
- A negative saving means the heat pump costs more to run at these prices.