Balcony Solar Savings Calculator
Estimate annual and monthly generation, bill savings and simple payback. Choose your panel direction and angle, then use your own electricity price and total installation cost.
Your estimated results
Example estimate shown. Change the inputs, then calculate your scenario.
- Annual generation
- 446 kWh
- Annual bill saving
- £70
- December–February output
- 85 kWh
- Simple payback
- 8.5 years
No export income, battery benefit or standing-charge saving is included. Payback assumes today's unit rate and your selected self-use stay constant; it excludes finance, degradation and replacement costs.
Compare verified kits and their mounting options →Check what belongs in your total cost →Estimated monthly output
Long-term monthly averages for London, 600 Wp, facing south, at 90°: vertical railing or wall. These are modelled, rather than measured or forecast, figures.
| Month | Generation | Bill saving at 60% self-use |
|---|---|---|
| January | 27.6 kWh | £4.36 |
| February | 31.7 kWh | £5.00 |
| March | 42.6 kWh | £6.73 |
| April | 46.2 kWh | £7.29 |
| May | 40.0 kWh | £6.32 |
| June | 37.8 kWh | £5.97 |
| July | 39.4 kWh | £6.21 |
| August | 41.0 kWh | £6.47 |
| September | 43.5 kWh | £6.87 |
| October | 38.1 kWh | £6.01 |
| November | 31.9 kWh | £5.03 |
| December | 26.0 kWh | £4.10 |
How we calculate these figures
We downloaded 216 PVGIS 5.3 simulations on 30 September 2026: twelve representative UK cities, six directions and three panel angles. Each uses the PVGIS-SARAH3 radiation database, 1 kWp of crystalline-silicon panels, free-standing mounting, the terrain horizon and 14% system losses. We scale its monthly and annual energy outputs to your panel rating and apply your additional shade allowance. The PVGIS losses are already included; we do not deduct them twice.
Annual saving = annual generation × unit rate ÷ 100 × self-use percentage ÷ 100. Simple payback = total fitted cost ÷ annual saving. Monthly generation is rounded separately, so displayed monthly totals may differ slightly from the annual result.
The model does not know your exact address, nearby buildings, panel temperature at your mounting position or your hourly electricity use. It does not simulate an 800 VA inverter's clipping. For a detailed design or a heavily shaded balcony, ask the supplier for a site-specific estimate. Modelling energy output does not establish that an installation is permitted.
You can reproduce a scenario using the Joint Research Centre's PVGIS API documentation. For London south-facing at 90°, use latitude 51.5074, longitude −0.1278, aspect 0, angle 90, peakpower 1 and loss 14.
Read our winter generation guide, north-facing balcony analysis and self-consumption guide to understand what changes the result.
One email when the list changes.
A new kit verified on the ENA register, or a retailer starting to sell one. Nothing else, and you can leave with one click.
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