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PlugInSun

Savings calculator

What could a plug-in solar setup save you?

Every number below is an estimate built from stated assumptions, not a guarantee. Adjust the inputs to match your home and read the assumptions before you rely on the result.

Your details

Capped at 800W, the current UK limit for this type of installation.

Plug-in solar only pays when you use the electricity as it is generated.

Conservative

£90 / year

Monthly
£8
Generation
560 kWh
Used at home
347 kWh
Payback
6.7 yrs
10-year total
£1,011

Central

£113 / year

Monthly
£9
Generation
700 kWh
Used at home
434 kWh
Payback
5.4 yrs
10-year total
£1,263

Optimistic

£130 / year

Monthly
£11
Generation
805 kWh
Used at home
499 kWh
Payback
4.8 yrs
10-year total
£1,453

Cumulative savings vs kit cost

Central scenario, ten years, including assumed electricity price rises and panel degradation.

  • Year 1£113
  • Year 2£228
  • Year 3£347
  • Year 4£468
  • Year 5£593
  • Year 6£721
  • Year 7£851
  • Year 8£985
  • Year 9£1,123
  • Year 10£1,263

The vertical marker shows the kit price of £649.

These figures are estimates, not guarantees. Real output depends on weather, exact mounting, shading through the day, inverter behaviour, and how much electricity you actually use while the sun is out. Savings only occur on electricity you consume at the time of generation — plug-in systems do not normally earn export payments.

Assumptions used in this calculation

Base annual yield
875 kWh per kWp
Regional factor
1
Orientation factor
1
Shading factor
1
Self-consumption share
62%
Annual degradation
0.5%

Scenario range applies a 80% conservative and 115% optimistic multiplier to generation.

How this plug-in solar savings calculator works

The calculator estimates how much electricity a plug-in solar system could generate in your part of the UK, adjusts it for the direction your panels face and any shading, then works out how much of that output your household is likely to use during daylight. That share is multiplied by your electricity unit rate to give an estimated annual saving, and compared with the system cost to give a payback period. Every assumption is listed above so you can see exactly where the numbers come from.

Savings depend most on how much electricity you use while the sun is up. Read how much plug-in solar can save and what an 800W system can power for the detail, or see our guide to the best plug-in solar kits in the UK when you are ready to shortlist a system.

Want the numbers checked against a real roof?

If your estimate suggests you need more than 800W, a full rooftop system is the honest answer. You can request rooftop quotes or read the how it works guide first.

Get the assumptions update

We email when tariff assumptions, regulations or recorded prices change.