PlugSolar.uk

Home / Savings calculator

Plug-in solar savings calculator

Tell us about your home and we'll estimate your annual savings and payback period in seconds.

The 800W cap is the UK legal maximum for plug-in solar AC output.

Typical UK standard variable rate is 22–25p/kWh (2026).

Smart export tariffs pay 12–15p; basic SEG rates pay 4–5p. 5p is a safe default.

Typical UK kits cost £400–£1,000 today; prices are falling as the market opens.

Estimated generation — kWh per year
Estimated savings — per year
Payback period — years
25-year net savings — after kit cost

How this calculator works

We use a simple, transparent model based on UK market data (August 2026):

  • Generation: an average UK installation produces around 0.95 kWh per watt per year when facing roughly south with a modest tilt. We adjust for your region - South England gets more sun, Scotland less.
  • Self-consumption: power you use yourself is worth your full electricity rate. Typical self-consumption is 30–40% without a battery (up to 50%+ if you work from home) and 70–80% with a battery.
  • Export: surplus power is sold back to the grid at your export rate. Octopus Outgoing pays around 12p/kWh; basic SEG rates are 4–5p.
  • Payback: kit price divided by annual savings. We assume panels degrade about 0.4% per year over their 25-year life, which trims long-term savings by roughly 5–7%.
Government estimate: the UK government says a typical household can save up to £110 a year and cover about 20% of average electricity use with plug-in solar. Your actual results depend on sunlight, orientation, shading and how much daytime power you use. (Source: GOV.UK, Aug 2026)

This calculator is an estimate for guidance only - it is not financial advice. Prices and tariffs change; always check the latest figures with your supplier.