This is the most useful thing on the site and it takes one table to show.
| Where it goes | Share of ideal roof | Why |
|---|---|---|
| Free-standing garden frame, 30 degrees south | 99 per cent | You control the angle and the direction. Nothing else lets you do that. |
| Pitched roof, 35 degrees south | 100 per cent | The reference case. Rarely available to a plug-in device. |
| Vertical south-facing wall | 74 per cent | Vertical is a poor angle for a UK sun, but south still helps a great deal. |
| Vertical east or west wall | 51 per cent | Wrong angle and wrong direction. Half the output for the same money. |
Averaged across all thirteen regions, from the PVGIS queries behind the calculator.
These are sold everywhere as balcony solar. For a lot of British homes that is the one place they may not go.
The right that lets you put solar up without asking was rewritten on 27 August 2026, and it now prohibits plug-in solar fixed to wooden walls, balconies and timber cladding. If your balcony is timber or timber clad, you are outside permitted development and would need a planning application for a device costing a few hundred pounds.
A balcony is also usually a vertical mounting facing whichever way the building faces, which on the table above is the 51 to 74 per cent case. So even where it is allowed, it is rarely the best spot available.
A frame in the garden, angled at about 30 degrees, pointed south. It is permitted, it avoids the timber problem entirely, and it gives you within one per cent of what a perfect roof would.
| Region | Garden frame | Roof pitch | South wall | East or west wall |
|---|---|---|---|---|
| South East | 890 | 897 | 645 | 424 |
| South West | 816 | 822 | 594 | 417 |
| East of England | 795 | 802 | 594 | 412 |
| Wales | 792 | 798 | 575 | 385 |
| London | 789 | 795 | 582 | 409 |
| East Midlands | 754 | 760 | 564 | 391 |
| West Midlands | 746 | 752 | 555 | 389 |
| Yorkshire | 729 | 736 | 550 | 376 |
| North East | 727 | 734 | 558 | 372 |
| Northern Ireland | 708 | 714 | 534 | 367 |
| North West | 684 | 689 | 505 | 359 |
| Scotland, south | 656 | 661 | 491 | 337 |
| Scotland, north | 623 | 628 | 470 | 321 |
Not sure which of these your spot counts as? Send us a description and we will tell you.
Tell us the postcode and where you are thinking of putting it. We will run the numbers for your exact spot rather than a regional average, and tell you if the permitted development rules rule it out before you spend anything.