Solar savings calculator
How much could solar save you? Built from your panel count, your roof direction and what metered homes in your area made. Add or remove panels to see how it moves.
Annual saving
£429–£827/year
12 panels (5.3 kWp). Bill savings plus export value, as a central ±20% range.
Estimated cost
£7,095–£11,070
Typical installed price
Payback
11.6–17.3yrs
Before it pays for itself
CO₂ saved
≈ 758kg
A year, against grid electricity
How that adds up
- Annual generation
- 3,829–4,730 kWh
- Used at home, about 29%
- 1,250–1,250 kWh
- Exported, the rest
- 2,579–3,480 kWh
- Bill savings (power you use yourself)
- £300–£375/yr
- Export income (the rest, sold back)
- £129–£452/yr
Where the benefit comes from
Shifts with your daytime usePast about 10 panels your home's own use is covered and the extra power is exported, which earns less than it saves. More panels still add export income.
Bill savings and export income are the two parts of your annual saving; the combined figure above is a central ±20% range rather than a single number.
Based on UK 2026 assumptions and your inputs. The cost and payback are ranges to plan around; a listed installer's survey gives the confirmed price for your exact roof. How we measure.
How it works
What this calculator works out.
Annual saving
The power you use yourself, valued at the price you pay for electricity, plus what the rest earns when exported under the Smart Export Guarantee. You can only use what your home needs, so past a certain panel count the extra is export.
Install cost
A fixed element for scaffold, inverter and connection paperwork, plus a per-kWp element for panels and labour. Battery storage is priced on top when you tick it.
Payback
Install cost divided by annual saving: the years before the system has paid for itself. A range, because every input is a range.
Annual generation
Kilowatt-hours a year for the panel count, from what metered homes in your postcode area facing the same way made. With an address, the roof read sets the direction and the starting count; without one, you set them.
The 2026 UK figures behind it.
Every result is a central estimate with a ±20% band. These are the inputs.
Electricity price
24–30p per kWh
Low end tracks the Ofgem price cap; high end covers non-direct-debit and regional spread.
Export tariff
5–13p per kWh
Smart Export Guarantee rates from a basic tariff up to the best flat rates.
Generation
677–838 kWh per kWp
Metered: the middle half of 14,879 real UK homes in 2024, cut by postcode area and roof direction for your estimate.
Install cost
£1,000 + £1,150–£1,900 per kWp
A fixed element for scaffold, inverter and connection paperwork, plus panels and labour by size.
Battery storage
£3,000–£6,000
A typical 5 kWh home battery, added only when you tick it.
Panels
400 W each
A modern domestic panel. Your roof sets the starting count when the imagery can size it, otherwise the metered median system (7 panels), and you add or remove from there.
Electricity use
2,500 kWh a year
Ofgem’s typical home unless you type your own. Solar can only replace power you use, so this caps the bill savings: past that, the extra is exported.
Grid carbon
0.177 kg CO₂ per kWh
UK electricity generation factor, DESNZ 2025. Applied to everything the panels make, exported power included.
| Input | Figure | What it covers |
|---|---|---|
| Electricity price | 24–30p per kWh | Low end tracks the Ofgem price cap; high end covers non-direct-debit and regional spread. |
| Export tariff | 5–13p per kWh | Smart Export Guarantee rates from a basic tariff up to the best flat rates. |
| Generation | 677–838 kWh per kWp | Metered: the middle half of 14,879 real UK homes in 2024, cut by postcode area and roof direction for your estimate. |
| Install cost | £1,000 + £1,150–£1,900 per kWp | A fixed element for scaffold, inverter and connection paperwork, plus panels and labour by size. |
| Battery storage | £3,000–£6,000 | A typical 5 kWh home battery, added only when you tick it. |
| Panels | 400 W each | A modern domestic panel. Your roof sets the starting count when the imagery can size it, otherwise the metered median system (7 panels), and you add or remove from there. |
| Electricity use | 2,500 kWh a year | Ofgem’s typical home unless you type your own. Solar can only replace power you use, so this caps the bill savings: past that, the extra is exported. |
| Grid carbon | 0.177 kg CO₂ per kWh | UK electricity generation factor, DESNZ 2025. Applied to everything the panels make, exported power included. |
How we read roofs, generation and savings: how we measure.
Common questions
Solar savings calculator FAQs.
How much do solar panels save in the UK?
A typical 4.5 kWp system comes out at roughly £400–£850 a year in this calculator, depending on roof direction, how much power you use during the day and whether you add a battery. Enter your address above for a figure built from your own roof and what metered homes near you made.
Why is the result a range and not one figure?
Electricity prices, export rates, install quotes and the weather all move. The calculator works from a central estimate and shows a ±20% band around it, which is a figure you can plan with. A listed installer’s survey gives you the confirmed price for your roof.
Does the estimate include a battery?
Only when you tick “Add battery storage”. A battery raises how much of your own generation you use at home, which lifts the annual saving, and adds its own cost, which lengthens payback. The result shows both effects.
Do I need to give my address?
No. Your house number and postcode let us read your roof from satellite imagery, so the direction and panel count come from your home rather than a guess, and that roof read is what lets you request quotes. Without an address, pick your panel count and roof direction and we price it from what metered homes in your postcode area made. Nothing is stored against your address; the estimate lives behind a short link in this browser.
How many panels do I need?
Most UK homes fit 8 to 12 panels, around 3.2–4.8 kWp. The useful number is the one that covers what you use by day: past that, every extra panel's power is exported at a lower rate, so the calculator names the point where your own use is covered. A bigger array still earns export income, and a battery lets you use more of it yourself.
What is the Smart Export Guarantee in this estimate?
The Smart Export Guarantee (SEG) is what your energy supplier pays for the electricity you export to the grid. The calculator values exported power at 5–13p per kWh and counts it as export income alongside the bill savings from the power you use yourself.
