Illustrative estimate — not a quotation For homes replacing a gas boiler in England, Scotland or Wales. No account or personal details required. Calculation stays in your browser.
1. Tell us about your home
On your annual energy statement. Not sure? 12,000 kWh is an illustrative starting point, not your home's measured use.Pre-filled with Ofgem national-average Direct Debit unit rates for Oct–Dec 2026. Your bill or fixed tariff may differ.
2. Installation and performance
Default assumes no grant. Grant figures are examples, not eligibility decisions. The £12,000 installation illustration is from Energy Saving Trust for an air source heat pump.
SCOP measures annual heat produced per unit of electricity. Real performance depends on installation, controls, heating temperatures and weather.
3. Your estimated costs
Enter valid non-negative figures within the displayed ranges.
Your current annual heating energy cost
Heat pump annual heating energy cost
Estimated installation cost
Estimated upfront cost after illustrative grant
Estimated difference in annual heating energy cost
No grant is assumed until confirmed.
How we worked this out
This compares the heating share of your current gas use with the electricity needed to provide the same useful heat. It excludes other household electricity/gas use, standing charges, future tariff changes, servicing, boiler replacement avoided, hot-water-system differences, extra radiators and finance costs.
Your next practical steps
- Check annual gas kWh and tariff unit rates on your bills.
- Obtain a whole-installation quote, including any radiator, cylinder and electrical work.
- Ask the installer for a heat-loss assessment and expected SCOP.
- Check grant eligibility independently before relying on a discount.
Ofgem tariff source · Energy Saving Trust installation guidance · GOV.UK grant conditions
Reference rates checked 30 October 2026. Values are illustrative and should be reviewed quarterly.