Demo: Example Solar Ltd is a fictional company. This shows what an installer’s own branded version of the calculator looks like. The figures are real and come from solarpaysback.com. The quote button goes to example.com.

Example Solar Ltd

How long would solar panels take to pay for themselves at your home?

Solar payback calculator

All amounts in pounds sterling.

Your home

Sets how much electricity each kW of panels generates in a year where you live.

kWh per month

Check your bill or your supplier’s app for kWh used. Average the last 12 months if you can.

pence per kWh

Starts at the Ofgem price cap unit rate for the South Western England region (Direct Debit, October to December 2026). Your bill shows your own unit rate.

Solar system
kW

Leave blank to size the panels to cover your yearly use, or enter the size on your quote.

Installed price

£1.78 per watt: the median for 0–4 kW systems in the latest government cost data. Your quote may differ.

Assumptions you can change
% per year

Starts at 0.5%, the median of nearly 2,000 reported rates in an NREL review.

% per year

A scenario, not a forecast. Try 0% and 5% to see how much it matters.

%

Share of the panels’ output your home uses as it is generated. 100% assumes all of it replaces electricity you would otherwise buy, up to your annual use.

A battery only adds savings when you use less than 100% of your solar power directly. Lower “Used directly at home” under assumptions to model that.

Results

Payback period

6.4years

Cumulative savings first cover the installed cost during year 7.

Installed cost
£4,882
Published median for 0–4 kW systems
First-year savings
£718
Savings over 25 years
£24,466
Net gain after 25 years
£19,584
Return over 25 years
401%
Net gain as a share of the installed cost
System size
2.7 kW
Sized to cover your yearly use
First-year generation
2,700 kWh
Cumulative savings over 25 yearsThe line crosses the installed cost in year 7: that is when the system has paid for itself.
Year-by-year table
Generation and savings for each of the 25 years
YearGeneration (kWh)Price per kWhSaved that yearSaved so farNet position
12,700£0.266£718£718-£4,164
22,687£0.274£735£1,453-£3,428
32,673£0.282£754£2,207-£2,675
42,660£0.290£773£2,979-£1,902
52,646£0.299£792£3,771-£1,110
62,633£0.308£811£4,582-£299
72,620£0.317£832£5,414£532
82,607£0.327£852£6,266£1,385
92,594£0.337£873£7,140£2,258
102,581£0.347£895£8,035£3,153
112,568£0.357£917£8,952£4,070
122,555£0.368£940£9,892£5,011
132,542£0.379£963£10,856£5,974
142,530£0.390£987£11,843£6,961
152,517£0.402£1,012£12,855£7,973
162,504£0.414£1,037£13,892£9,010
172,492£0.427£1,063£14,955£10,073
182,479£0.439£1,089£16,044£11,163
192,467£0.453£1,116£17,161£12,279
202,455£0.466£1,144£18,305£13,423
212,442£0.480£1,173£19,477£14,596
222,430£0.494£1,202£20,679£15,797
232,418£0.509£1,232£21,910£17,029
242,406£0.525£1,262£23,173£18,291
252,394£0.540£1,293£24,466£19,584

Savings count only electricity your home no longer buys. Power sent to the grid is valued at zero. Grid emissions data has not been verified yet, so no carbon figure is shown. See the methodology for every formula and source.

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Calculator by Solar Payback CalculatorFigures for the UK, from published sources