UK Solar Payback Calculator
Solar savings, made simple
This calculator helps you test the numbers in a solar quote. It is a guide, not a promise.
How to use it: choose your home, change one number at a time, then read the new result. Use your quote and energy bill if you have them.
Your numbers
Choose a home type. Then change any number you know. Electricity prices are in pence per unit (kWh).
Medium-use home. The postcode check uses Postcodes.io and PVGIS. We save the solar result, not your postcode.
The starting numbers come from Ofgem. Roof direction and shade change the solar estimate. A postcode gives a more local estimate.
Your estimate
This result includes bill savings, export payments and your upkeep budget. It does not include loans, roof work, future price changes or replacement parts.
How to read the result
If payback only works with very optimistic self-consumption or export assumptions, treat that as a warning. If the result looks close, ask a provider to explain how their quote estimates generation and savings.
Useful sources: Ofgem SEG, GOV.UK VAT relief.
How does the solar payback calculator work?
It adds the money saved on your electricity bill to the money earned from spare solar power. It then takes away the yearly upkeep budget.
- Bill saving: solar power used at home × the grid price.
- Export income: spare solar power sent to the grid × the export rate.
- Yearly benefit: bill saving + export income − yearly upkeep.
- Simple payback: full installed price ÷ yearly benefit.
Simple payback: £7,000 ÷ £514 is about 13.6 years.
This is an example, not a typical result or promise. Change the settings to match your quote, roof and energy bill.
How to use the answer
The calculator adds two things: money saved by using solar power at home, and money earned by sending spare power to the grid.
Try two versions
- A careful case with a higher cost and lower savings.
- A best case with a lower cost and higher savings.
If the two answers are very different, ask the installer to explain the numbers that matter most.
What is not included?
The result may not include loan interest, roof work, future electricity prices, repairs or replacement parts. Keep these costs in mind before you decide.
Choose an export-rate scenario: shortlist current flat-rate offers in the solar export tariff finder, then test a conservative rate here.
Sources and official guidance3
Before using annual generation: sense-check the installer figure with the solar output and quoted-yield guide.
Keep each quote’s inputs separate: record them in the three-quote worksheet before testing payback.
Optional next step
Want to compare this result with a home quote?
Keep your numbers nearby and ask each installer to explain any different costs or savings.
- No pressure from Here4Solar
- Personalised home quote
- Check if solar could work
Compare at least three written quotes before choosing an installer.