Free UK tool
Solar Panel Payback Estimator
Are solar panels worth it in the UK at 2026 prices? Pick a system size, enter your actual quote and electricity rate, and see your yearly saving, SEG export income, and the honest payback period in years.
This free estimator uses a mid-UK generation figure of about 850 kWh per kWp per year and splits your bill savings (power you use yourself) from your export income (power sold back under the Smart Export Guarantee). No signup, no email — just the maths.
Generation and cost figures are typical published values — not a site survey. A shaded or north-facing roof will generate meaningfully less.
Pre-filled with a typical UK installed price for this size — replace it with your real quote.
On your bill. Default is a typical capped rate.
Smart Export Guarantee tariffs range roughly 3p–15p+; check suppliers.
Self-used power saves your full unit rate; exported power earns the lower SEG rate, so using your own generation is worth far more.
Your solar payback
3,825
kWh generated per year
£755
per year (£469 bills + £287 export)
8.6 yrs
payback on £6,500
£8,609
net gain over 20 years at today's rates
That's around the UK average payback. It improves if electricity prices rise, if you shift more usage into daylight hours, or if you add a diverter for hot water.
How the maths works
Each kWp of panels on a decent UK roof generates roughly 850 kWh a year — more in the south-west, less in Scotland, less again on a shaded or east-west roof. The power you use yourself saves your full unit rate (24.5p by default); the surplus is exported under the Smart Export Guarantee at whatever rate your supplier pays. Bill savings plus export income gives your yearly return, and the payback is simply the installed cost divided by that return.
Two honest caveats. First, this assumes today's prices stay flat — in practice energy prices moving up shorten the real payback, and SEG rates change. Second, it ignores maintenance and the inverter replacement most systems need around year 12–15, which typically costs £800–£1,200. Treat the 20-year figure as optimistic and the payback figure as the number that matters.
Common questions
Are solar panels worth it in the UK in 2026?
For most homes with a decent roof, yes — typical payback is 7–12 years against panels warranted for 25. The case is strongest if you're home in the day, have an EV or immersion heater to soak up surplus, or can pair the system with a battery.
How much does a 4.5 kWp solar system cost in the UK?
Installed prices for a typical 4.5 kWp system sit around £5,500–£7,500 depending on roof access, scaffolding and the inverter and panel brands chosen. Always get three quotes — spreads of £2,000 for identical kit are common.
What is the Smart Export Guarantee and how much does it pay?
The SEG requires larger suppliers to pay you for exported solar electricity. Rates vary widely — from around 3p to over 15p per kWh on the best tariffs — so switching your export tariff is one of the easiest wins after installation.
Does a home battery improve solar payback?
A battery lifts self-use from roughly 30–50% to 70%+, which converts cheap exported power into full-rate bill savings. Whether the battery itself pays back depends on its installed cost and your tariff — it stacks best with a time-of-use tariff that lets it charge cheap overnight in winter.