Direction & shading
Is my roof suitable for solar panels? The checklist
Roof suitability decides more of solar's economics than any equipment choice — a brilliant panel on a bad roof loses to an ordinary panel on a good one.Here are the six checks, roughly in order of importance, and what to do if your roof fails them.
Written and edited by Christopher Panteli
Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.
The six checks
- Direction: south-facing captures the most annually; east or west costs some output but works — see east vs west; north-facing usually undermines the case.
- Pitch: most UK pitched roofs (roughly 30–45°) are already close to ideal; flat roofs use angled frames instead.
- Shading: chimneys, dormers, trees and neighbouring buildings cast moving shadows; even partial shade cuts output disproportionately. Watch the roof across a full day if you can.
- Space: each residential panel needs roughly two square metres of clear roof (see panel sizes); obstructions and edge margins shrink the usable area.
- Structure: the roof must carry the added load; older or unusual structures may need a structural check.
- Condition and age: panels last decades — putting them on a roof that needs recovering within ten years buys an expensive remove-and-refit later.
How to check without climbing anything
A compass app (or Google Maps satellite view) gives your roof's direction. Shading you can judge from the ground across a sunny day — morning, midday, late afternoon. Space is measurable from satellite imagery. Structure and condition are the two that justify a professional: a surveyor or reputable installer should inspect before quoting, and any quote made without seeing the roof (even remotely) deserves suspicion. For the output side, the calculator turns direction and shading into an actual annual estimate.
If your roof fails the checklist
A poor roof doesn't end the story. Ground-mounted frames in a garden often out-perform a compromised roof; wall mounting can work on a sunny gable; flat roofs take ballasted frames. And the option designed exactly for people without usable roofs — plug-in solar on a balcony, fence or patio — is waiting on the UK's legal green light: it is not yet legal to sell, supply or use, with the consultation response awaited.
Listed or conservation-area homes
Frequently asked questions
- Which roof direction is best for solar panels?
- South-facing, at a typical UK pitch. East- and west-facing roofs yield noticeably less but often remain worthwhile — and an east-west pair spreads generation across the day. North-facing roofs usually weaken the economics badly.
- Can my roof hold solar panels?
- Most sound modern roofs can — panels and mounting add a modest distributed load. But structure and remaining roof life should be checked by a professional before installation, especially on older properties, because refitting panels after later roof repairs is expensive.
Sources
- 1. PVGIS (Photovoltaic Geographical Information System) — European Commission, Joint Research Centre
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