greenhomesums
Are solar panels worth it in the UK? Calculator + honest verdict
For most UK homes solar panels pay back in 7-11 years and save £15,000+ over 25 years. Enter your postcode for a personalised estimate. Powered by PVGIS satellite data.
Are solar panels worth it in the UK?
For most UK homes with a south- or southwest-facing roof, yes. A typical 4 kWp system costs £5,500–£8,500 to install in 2026, pays back in 7–11 years, and delivers £12,000–£18,000 in net savings over 25 years. The case is strongest when you have high daytime electricity use, a good SEG export tariff, or plan to add an EV or heat pump.
The three conditions that make solar clearly worth it:
- South-, southeast- or southwest-facing roof with minimal shading
- Electricity use above 2,500 kWh/yr (average UK home uses ~3,500 kWh)
- Planning to stay in the property for at least 8–10 years
Use the calculator below for a figure specific to your postcode, system size and household.
| Scenario | Install cost | Payback | 25-yr net saving |
|---|---|---|---|
| South England, no battery | £6,500 | 7–8 yrs | ~£17,000 |
| Midlands, no battery | £6,500 | 8–9 yrs | ~£15,000 |
| Scotland, no battery | £6,500 | 10–12 yrs | ~£12,000 |
| Midlands + 5 kWh battery | £9,500 | 11–13 yrs | ~£16,000 |
| Midlands + battery + EV | £9,500 | 9–11 yrs | ~£20,000 |
Interactive calculator
Worked example
A 4 kWp system on a typical UK home using 3,500 kWh/yr of electricity:
| System | 4.0 kWp |
|---|---|
| Generation | 3800 kWh/yr |
| Year-1 saving | £730 |
| Payback | 8.5 yrs |
| 25-yr net benefit | £23185 |
You'll probably want this next
Solar makes most sense when paired with a cheap export tariff
See which UK suppliers pay best for the electricity you send to the grid.
Check Octopus Agile →Frequently asked questions
- Where does the solar irradiance data come from?
- PVGIS — the European Commission Joint Research Centre's open satellite-derived dataset. Our [solar payback by postcode page shows sample yields for every major UK city.
- What is the Smart Export Guarantee (SEG)?
- A scheme requiring large UK energy suppliers to pay you for each kWh of electricity you export to the grid. Use our [SEG tariff comparator to see which supplier pays best — rates range from 2.5p to 15p+ per kWh.
- How accurate is the estimate?
- Within ~10% for typical UK homes. Actual yield varies with roof orientation, shading and panel quality. For a per-city breakdown with regional context see [solar payback by UK city.
- Should I add a battery?
- A battery usually extends payback by 3–5 years but increases lifetime savings if your SEG export rate is much lower than your import rate. Model it in this calculator, or compare the whole stack in our [solar + battery + EV combined calculator.
- Does solar pair well with a heat pump?
- Directly, yes — a heat pump running on free solar electricity is one of the cheapest heating setups in the UK. See the [heat pump vs gas boiler calculator and check [BUS grant eligibility for £7,500 off the install.
- What solar panel size do I need for a UK home?
- Most UK homes suit a 3.5–4.5 kWp system (roughly 8–11 panels). A 4 kWp system generates around 3,400–4,100 kWh/year depending on location and produces enough to cover 50–80% of typical household usage. Adjust the system size slider in this solar panel calculator to see exactly how size affects your payback and savings.
- Are solar panels worth it in 2026?
- Yes, for most UK homes with a south- or southwest-facing roof. The economics improved significantly in 2025–26: VAT remains zero-rated, install prices have fallen to £5,500–£8,500 for a 4 kWp system, and electricity prices are still around 27p/kWh on the Ofgem cap — making every kWh you self-consume genuinely valuable. A typical 4 kWp install in the Midlands pays back in 8–9 years and delivers around £15,000 in net savings over 25 years. The case is strongest if you're also considering an EV or a heat pump, both of which dramatically increase the value of self-consumed solar.
- Why are solar panels not worth it for some UK homes?
- Several scenarios tip the economics the wrong way. A north-facing or heavily shaded roof can lose 25–35% of expected yield, pushing payback past 15 years. A very small household (under 2,000 kWh/yr) that exports most generation at 5–8p/kWh instead of self-consuming at 27p/kWh will see poor returns without a battery. Homes planning to sell within 5 years are unlikely to recoup the install cost in the sale price. And if your roof needs replacement in the next decade, it's worth doing that first — removing and refitting panels adds £500–£1,500. Use this calculator to model your specific situation rather than relying on installer quotes, which tend to use optimistic assumptions.
- How long do solar panels take to pay back in the UK?
- Payback in the UK typically ranges from 7 to 12 years depending on location, system size, how much electricity you use at home during the day, and your SEG export rate. A 4 kWp system in southern England with a 15p/kWh SEG rate and a household using 3,500 kWh/yr typically pays back in 7–8 years. The same system in Scotland or with a low 5p/kWh export rate may take 10–12 years. Adding a battery usually extends payback by 2–4 years but increases total savings. Enter your postcode above for a figure specific to your region.
How this calculator works
The Solar Panel Savings Calculator turns five inputs — system size, household usage, tariff, Smart Export Guarantee (SEG) rate and install cost — into a single year-by-year cash-flow model out to year 25. At the heart of it is PVGIS, the European Commission Joint Research Centre's open satellite-derived irradiance dataset, which tells us roughly how many kilowatt-hours each kilowatt-peak (kWp) of panels will generate in your part of the UK over a year. The UK ranges from about 850 kWh/kWp in Glasgow up to around 1,035 kWh/kWp on the south coast; we use 950 kWh/kWp as a national default and your postcode to refine it.
Once we know the annual generation, we split it into two buckets: the portion you consume yourself (worth your full import tariff, typically around 27p/kWh at the current Ofgem cap ) and the portion you export (worth your SEG rate, usually 8–15p/kWh depending on supplier). We use a self-consumption fraction that scales with household usage — bigger households consume more of their own generation, and a battery lifts that fraction further. Your year-one saving is the sum of the avoided imports plus the export income. Subsequent years apply electricity-inflation compounding so that the undiscounted 25-year figure reflects the real-cash benefit, not a today-money approximation.
Common pitfalls and things people get wrong
- Orientation and tilt. PVGIS defaults assume a south-facing roof at about 35° tilt. East-west splits typically lose around 15% of annual yield; a steep north-facing pitch can lose 30% or more. If your installer is quoting an east-west split, ask for a PVGIS-modelled yield for your specific roof rather than the marketing brochure number.
- Self-consumption. A 4 kWp system on a small household that is out all day will export 60–70% of its generation. Adding a 5 kWh battery typically lifts self-consumption from about 35% to 55–65% — which is a bigger financial swing than most glossy quotes show, because each exported kWh earns roughly half what a self-consumed kWh saves.
- SEG rate variation. The Smart Export Guarantee does not mandate a rate — only that large suppliers must offer one. In 2026 SEG tariffs range from Octopus Outgoing at 15p/kWh down to some incumbents at 5p/kWh. If you are on a 5p SEG, your payback is noticeably longer; always optimise for tariff after install — our Octopus Agile calculator shows what the best import-side tariff can do alongside it.
- Install-cost drift. UK install prices for a 4 kWp system typically sit between £5,500 and £8,500 in 2026. Quotes at the low end are usually bare-bones (no battery, cheap inverter); quotes above £9,000 often include a battery and a premium inverter. Paying £10,000 for panels alone is rarely competitive.
UK-specific context
VAT on domestic solar installation in the UK remains zero-rated through at least March 2027 for panels and batteries installed as part of the same job, which is the main reason 2025–26 is a good window to install. The SEG is not a feed-in tariff — you are not locked in; you can switch export supplier each year just like your import supplier, and it is normal to be on SEG with one supplier and import with another. Planning is permitted-development for almost all domestic roof-mounted systems unless you are in a conservation area or a listed building.
When this isn't the right answer
This calculator assumes a straightforward roof install on a grid-connected home. It does not model shading (a single chimney can cost 10–20% of annual yield without microinverters or optimisers), inverter replacement at year 10–12 (budget £1,000–£1,500), or the case where you are planning to add a heat pump and EV — both of which dramatically increase the value of self-consumed solar and the economic case for a battery. If your circumstances are unusual (off-grid, export-limited by DNO, flat roof with ballast), treat the payback figure as a ceiling and get a PVGIS-based proposal from an MCS installer.
When solar panels are not worth it
Solar is not right for every home. The economics tip the wrong way in these situations:
- North-facing or shaded roof. A north-facing roof generates 25–35% less than a south-facing one. Heavy shading from trees or neighbouring buildings can cut yield further. If your roof faces north or has significant shading, ask your installer for a PVGIS-modelled yield specific to your roof — not a brochure figure.
- Very low electricity use. A small household using under 2,000 kWh/yr will export most of its solar generation. At 5–8p/kWh export (common on basic SEG tariffs), that income is poor compared to the 27p/kWh you save by self-consuming. Without a battery, payback stretches past 14 years. The SEG tariff comparator shows which suppliers pay most for exports.
- Selling within 5–7 years. Solar adds value to a property, but rarely enough to fully recoup install cost in a short-horizon sale. Estate agents typically add £3,000–£5,000 to valuations for solar — below the average install price.
- Roof needing replacement soon. Removing and refitting panels when the roof is redone adds £500–£1,500. If your roof is due within the next decade, replace it first or factor the cost into the payback calculation.
- Poor SEG rate with no battery. If you end up on a 3–5p/kWh SEG tariff and export 60%+ of generation, the case weakens significantly. Always switch to the best available SEG tariff after install — you're free to change export supplier independently of your import tariff.
Related calculators
Ranked by topic overlap with this tool.
- Solar battery storage UK — cost, savings & payback calculator — Combined savings from solar + battery + EV charging — compounding interactions, 15-year payback on the whole stack.
- Solar Export Tariff Comparator UK — Compare UK SEG tariffs side-by-side — Octopus, E.ON, British Gas, EDF and more. See exactly what each pays for your export kWh.
- Home battery storage UK without solar — cost, payback & is it worth it? — Home battery storage UK without solar: costs £2,800–£5,500, pays back in 7–10 years on Octopus Flux. Personalised payback calculator. If you have solar, see the solar battery storage calculator.
- Octopus Cosy vs Flux Tariff Comparator UK — Side-by-side comparison of Octopus Cosy (heat-pump-tuned), Flux (battery-tuned) and the standard variable. Annual £, peak-window share, export income.
- Solar Panel Payback Calculator UK — By Postcode — Simpler postcode-first variant with regional samples for major UK cities.