Solar payback calculator

Work out roughly how long solar panels (and a battery) take to pay for themselves. Everything runs in your browser.

Default 900 kWh per kWp is a typical UK average (roughly 800 in Scotland to 1,100 on the south coast). Local area pages, published nightly, give a PVGIS figure for your district.

Default assumptions: 4 kWp system costing £6,500, 50% of generation used at home, electricity 25p/kWh, export 12p/kWh. Heat pump SCOP 3.0, boiler 85% efficient, gas 6.5p/kWh, 12,000 kWh heat demand, £12,500 install less the £7,500 Boiler Upgrade Scheme grant. These are rounded 2026 UK typical figures - change any of them to match your bills and quotes.