The short answer
Yes, for around 80% of UK homeowners. A typical 4kWp installation in southern England produces 8–10 year payback and 25-year net benefit of £14,000–£22,000. In Scotland the figures soften to 9–11 year payback and £11,000–£17,000 net benefit, but the Home Energy Scotland interest-free loan often makes the cashflow easier.
What actually drives ROI
- Self-consumption rate (most important) — Without a battery, typical UK self-consumption is 25–35%. With a battery, 65–80%.
- Grid electricity price — Every 5p/kWh increase shortens payback by ~12 months.
- SEG export rate — Switching to Octopus Outgoing Flux from a 5p SEG can add £100–£200/year.
- Local irradiance — Brighton vs Glasgow is a ~15% difference in generation.
- Install quality — A 10% cheaper but poorly-optimised quote often delivers 15–20% less yield.
Worked example: 4kWp in southern England (2026)
| Install cost | £7,200 |
| Annual generation | 3,900 kWh |
| Self-consumed (40% × 27p) | £421 |
| Exported (60% × 15p SEG) | £351 |
| Annual benefit | £772 |
| Simple payback | 9.3 years |
| 25-year net benefit | £12,100 |
Adding a 5kWh battery typically lifts the annual benefit to £950+ and shortens payback to under 9 years.
When solar isn't worth it
- Predominantly north-facing roof with no east/west alternative
- Major chimney or tree shading between 9am–4pm
- Planning to move within 3 years
- Roof needs replacement within 10 years
- Short-tenure tenancy or absentee landlord arrangement
- Very low daytime electricity use (under 1,500 kWh/year) and no plans for EV/battery
Don't forget electricity price inflation
The Ofgem cap rose from 14p/kWh in 2020 to over 30p/kWh in late 2022, and remains around 25–28p in 2026. Solar effectively locks in your generation cost at ~6p/kWh for 25 years — the most powerful inflation hedge most households can buy.
Run your own numbers in the solar savings calculator, or check whether you qualify for funding on our UK grants page.
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Frequently asked questions
01.Is solar worth it in the UK in 2026?
Yes — for owner-occupiers with a south, southeast, southwest, east or west-facing roof and average daytime occupancy, solar typically returns 8–12% IRR over 25 years, comfortably beating most savings products.
02.When is solar NOT worth it?
Avoid solar if: your roof is heavily shaded, faces strict north, you plan to move within 3 years, you have very low daytime electricity use, or your roof needs replacement within 10 years.
03.Does solar add value to a UK home?
Multiple UK studies (Solar Energy UK 2024, Halifax 2023) suggest solar adds £1,800–£3,500 of value, plus shortens time-to-sale by an average of 8 days.
04.Will electricity prices keep rising?
The Ofgem cap has more than doubled since 2020. Even with falls in 2025–26, long-term forecasts project 3–5% real-terms annual rises in unit prices through 2035. Solar effectively locks in your generation cost at ~6p/kWh.