Calculate solar panel payback
Enter installation cost, annual generation, self-use percentage and export tariff. The calculator estimates your solar payback period from bill savings and export income.
Estimated annual benefit: £699.98 before any extra maintenance costs.
Solar panel payback formula
Solar payback compares the net installation cost with the annual benefit from electricity you use at home and electricity you export.
net install cost = installation cost - grants
bill saving = self-consumed kWh × import electricity rate
export income = exported kWh × export tariff rate
payback years = net install cost ÷ net annual benefit
Why self-consumption matters
Self-consumption is the solar electricity you use at home instead of buying from the grid. It usually has a higher value than exported electricity because it avoids buying electricity at your import rate.
A smart meter, daytime usage and battery storage can all affect how much solar electricity is used at home.
Bill saving
Each kWh used at home avoids buying that electricity from your supplier.
SEG income
Exported electricity may earn income through a supplier export tariff.
Net benefit
Bill savings plus export income are compared with the upfront cost.
Smart Export Guarantee and export tariffs
The Smart Export Guarantee is the current scheme that allows eligible small-scale generators to receive payments from electricity suppliers for electricity exported back to the grid.
Export tariff rates vary by supplier and tariff. A higher export rate improves solar payback, but the biggest saving often comes from using more of your generated electricity at home.
Should you include a battery?
A battery can increase the share of solar electricity used at home, but it also increases installation cost. The calculator lets you model this indirectly: increase installation cost and raise the self-consumption percentage to test the effect.
Compare your full electricity bill
Estimate your annual energy bill before and after changing electricity use.
What affects solar panel payback?
Solar payback can change a lot between homes. The calculator is a planning estimate, not a quote.
- Installation cost: higher upfront cost lengthens payback.
- Annual generation: roof direction, shading, system size and location affect output.
- Self-use: using more solar electricity at home often improves savings.
- Import rate: higher electricity prices increase the value of avoided imports.
- Export tariff: higher SEG/export rates increase income from exported electricity.
- Maintenance and inverter costs: extra costs reduce net annual benefit.
What to do before requesting solar quotes
Before speaking to installers, check your electricity usage, roof suitability, likely generation, whether you use power during the day, and whether you want battery storage.
Compare energy-saving options
Solar may not be the first upgrade for every home. Insulation or heating improvements can sometimes have a quicker payback.
Solar panel payback calculator FAQs
How do I calculate solar payback?
Divide net installation cost by the annual benefit from bill savings and export income.
What is a good solar payback period?
It depends on installation cost, generation, electricity prices, export tariff and how much solar electricity you use at home.
Does export income count toward payback?
Yes. Export tariff income can reduce the payback period, especially if you export a lot of electricity.
Does the calculator include battery storage?
It does not calculate battery performance separately. To model a battery, increase installation cost and adjust the self-consumption percentage.