Payback & Savings Calculator
Transparent figures based on real UK solar data. See exactly what each kit generates, saves, and when it pays for itself.
How we calculate
Solar yield: 900 kWh per kWp installed per year
This is the UK average for south-facing panels with no shading (source: MCS, Energy Saving Trust).
Electricity rate: 24.5p per kWh (Ofgem price cap, Q2 2026)
Self-consumption: We show realistic ranges
At 100% utilisation: you use every kWh generated. At ~60-70% utilisation: typical for daytime-only use without battery storage.
Max kit bonus: The PatioSun Max uses Tigo-optimised N-Type panels that deliver ~15% more real-world generation than standard panels (better performance in partial shade, cloud cover, and low light).
Monthly Generation & Savings
PatioSun Lite (400W)
360 kWh/year · Estimated monthly generation & savings at 24.5p/kWh
PatioSun Duo (800W)
720 kWh/year · Estimated monthly generation & savings at 24.5p/kWh
PatioSun Max (800W)
828 kWh/year · Estimated monthly generation & savings at 24.5p/kWh
Annual Savings Summary
| Kit | Output | Annual kWh | 100% use | 60% use | Realistic | Payback |
|---|---|---|---|---|---|---|
| PatioSun Lite | 400W | 360 kWh | £88/yr | £53/yr | £75–90/yr | ~6 yrs |
| PatioSun Duo | 800W | 720 kWh | £176/yr | £106/yr | £120–130/yr | ~5 yrs |
| PatioSun Max | 800W | 828 kWh | £203/yr | £122/yr | £150–170/yr | ~4 yrs |
25-Year Cumulative Savings
See when each kit crosses into pure profit — and how much you save over the 25-year panel guarantee.
PatioSun Lite
£449 cost · £75–90/yr saving · Breakeven ~year 6
PatioSun Duo
£549 cost · £120–130/yr saving · Breakeven ~year 5
PatioSun Max
£599 cost · £150–170/yr saving · Breakeven ~year 4
Lifetime Savings (25 Years)
PatioSun Lite
total energy savings
after kit cost of £449
PatioSun Duo
total energy savings
after kit cost of £549
PatioSun Max
total energy savings
after kit cost of £599
Battery Storage = Even Higher Savings
Without a battery, excess energy generated during peak sun hours goes back to the grid unused. With the upcoming Hoymiles HiBattery, you can store that excess and use it in the evening — pushing your self-consumption rate from ~60% towards 90%+. This means your real savings move closer to the 100% utilisation figures above. Battery pricing and updated savings calculations will be published here when available.