Plug-in solar savings calculator

Estimate annual savings, export income, and payback for a plug-in solar kit.

kWh means kilowatt hours: the units your electricity supplier uses on your bill.

The total wattage of your plug-in solar panels, e.g. 800 for two 400W panels

How much electricity your home uses per day on average. A typical UK home uses 8-10 kWh per day.

What your electricity supplier pays you for exported solar. Check your supplier's SEG tariff - typically 1 to 12 pence per kWh.

The percentage of solar electricity you use directly rather than exporting. Run appliances during the day to increase this. Most homes without batteries are around 30%, homes with someone in during the day are around 50-70%.

What you paid (or expect to pay) for your plug-in solar kit including panels, inverter, and mounting.

Adjusts the UK-average sunlight assumption. Pick the closest match — the default suits most unshaded installations.

Your estimate

£136

Total annual benefit

£18

Annual SEG income from exports

2.6 years

Payback period

Annual solar generation
876 kWh per year

Based on UK average sunlight (~4 peak sun hours/day) and a 75% system performance ratio (accounting for inverter, wiring, temperature, and shading losses). Actual generation varies by location, orientation, and weather - use PVGIS for a location-specific estimate.

Electricity you use from solar
438 kWh per year
Electricity you export to the grid
438 kWh per year
Annual savings from using your own solar
£118
Annual SEG income from exports
£18
Total annual benefit
£136
Payback period
2.6 years

Note

These are estimates based on your chosen sunlight condition, a 75% system performance ratio, and a default import price of 27p per unit. Your actual savings depend on your panel orientation, weather, and when you use electricity. The SEG rate field is yours to set — check your supplier's current tariff and change it. For a personalised generation estimate, use the free PVGIS tool.

Read our full plug-in solar savings guide