Calculate your solar panel costs, annual savings, and payback period with low, typical, and optimistic scenarios — based on 2026 UK data.
No sign-up. No affiliate links. Just the numbers.
System size
Most UK homes need 4–5 kWp
Affects annual sunlight hours
Battery storage
~10 kWh home battery
Ofgem cap: 26.11p (Aug 2026)
System cost
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System cost
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System cost
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| Year | Generation | Annual saving | Cumulative |
|---|
Estimates only. Assumes a flat electricity unit rate throughout. Does not model electricity price inflation, shading losses, or inverter replacement costs (~£800–£1,200 after ~10–12 years). VAT on solar installations is currently 0% until March 2027.
The same solar system can produce very different financial returns depending on how it's installed, how you use your electricity, and which energy tariff you're on.
Think: full-time commuter, budget installer, no tariff switching.
Based on empirical UK self-consumption data from 302 households.
Think: home worker, MCS-certified installer, actively manages tariff.
A solar installation quote covers several components. The panels themselves are only around 20–30% of the total — most of the cost is labour, inverter, and mounting hardware.
Solar panels
Cost has fallen 70%+ since 2010. Premium brands add longevity.
Inverter
Converts DC to AC. Expect to replace once in 25 years (~£800–£1,200).
Mounting & cabling
Roof-specific rails, DC/AC wiring, isolators.
Scaffolding
Typically £600–£1,000. Unavoidable for most pitched roofs.
Labour & commissioning
Usually 1–2 days for an MCS-certified team. Includes DNO notification.
These are installed costs including all labour. VAT is currently 0% on solar panels until 31 March 2027 — worth £750–£1,500 on a typical system.
| System | Low | Typical | High |
|---|---|---|---|
| 3 kWp | £5,000 | £5,400 | £5,850 |
| 4 kWp | £6,400 | £7,200 | £7,800 |
| 5 kWp | £8,000 | £9,000 | £9,750 |
| 6 kWp | £9,600 | £10,800 | £11,700 |
Prices based on MCS-certified installers. Battery storage costs an additional £5,500–£7,500 for a 10 kWh unit.
Always get 3 quotes
Prices vary by 30–40% between installers for identical systems. Only use MCS-certified installers — this is required to claim SEG payments.
Your actual savings depend on six factors. Some you control, some you don't.
South-facing roofs at 30–45° tilt generate the most. East/west-facing panels produce ~15–20% less but spread generation across more of the day. South Coast gets ~20% more sunlight than Scotland.
The more generated electricity you use directly (rather than export), the more you save. Home workers, EV chargers timed to solar generation, and dishwashers set to run at midday all boost this figure.
Each unit of solar power you use directly saves you the current unit rate (26.11p as of August 2026). Higher energy prices mean bigger savings. You can edit the rate in the calculator above.
Electricity you export to the grid earns a Smart Export Guarantee payment. Rates range from 12p (basic tariff) to 25p/kWh (supplier-installed, Good Energy 2026). Switching can add £100+/year.
Standard panels degrade at ~0.6–0.8% per year. Premium TOPCon and HJT panels degrade at 0.3–0.4%, generating measurably more over 25 years. Quality costs more upfront but pays back over time.
A 10 kWh battery stores surplus midday generation for evening use, lifting self-consumption from ~45% to 65–80%. Adds £5,500–£7,500 to install cost. Currently 0% VAT until March 2027.
A 4 kWp system in Cornwall generates around 900 kWh more per year than the same system in northern Scotland — worth roughly £230 at current rates.
| Region | kWh/kWp/yr | 4 kWp yield |
|---|---|---|
| South Coast | 1,025 | 4,100 kWh |
| South England (default) | 975 | 3,900 kWh |
| Midlands | 925 | 3,700 kWh |
| North England | 875 | 3,500 kWh |
| Scotland | 850 | 3,400 kWh |
PVGIS data. Assumes south-facing roof at 35° tilt, no shading.
A home battery captures surplus midday generation you'd otherwise export at a low rate, storing it for evening use at full import price.
Good fit for a battery
High evening electricity use, EV charging overnight, 5+ kWp system, willing to switch to a time-of-use tariff like Intelligent Octopus.
Battery may not stack up
Small system (3 kWp), modest evening use, or if you're away from home a lot. Payback often extends to 12–16 years.
The 0% VAT window
Batteries currently qualify for 0% VAT until 31 March 2027, saving up to £1,300.
kWp × regional kWh/kWp/yr
Regional yields from PVGIS. Assumes south-facing, 35° tilt, no shading. Shading reduces yield by 10–25%.
(gen × SCR × import) + (gen × (1−SCR) × SEG)
SCR = self-consumption ratio. Import rate editable above. SEG varies by scenario (12p / 15p / 20p).
gen_N = gen₀ × (1 − rate)^(N−1)
Rates: 0.8% / 0.6% / 0.4% per year. Based on NREL meta-analysis of 54,000+ systems.
Year when cumulative savings ≥ system cost
Calculated year by year. Excludes inverter replacement (~£1,000 at year 10–12) and electricity price inflation.
Read our full guides on costs, battery storage, and the Smart Export Guarantee before you get quotes.