The quick answer
In the UK, solar panels perform best facing due south at a pitch of 30–40°. But here's what most homeowners don't realise: your roof almost certainly doesn't need to face perfectly south.
- South — 100% (optimal)
- South-east / south-west — 95–97% (only 3–5% loss)
- East / west — 80–85% (still very worthwhile)
- North — 50–65% (usually not recommended)
The takeaway: any roof within about 45° of south is effectively fine. The difference between a perfect south roof and a south-east roof is smaller than the impact of a single shading tree. Don't assume your roof is unsuitable just because it isn't exactly south.
Output by orientation (full table)
These figures show annual output as a percentage of an optimal south-facing system, for a typical UK location at a standard 30–35° pitch. Figures are based on MCS MIS 3002 yield estimates for central England.
| Roof orientation | Azimuth | Output vs south | Verdict |
|---|---|---|---|
| South | 180° | 100% | Optimal |
| SSE / SSW | 150°/210° | 95–97% | Excellent |
| SE / SW | 135°/225° | 90–95% | Excellent |
| ESE / WSW | 112°/248° | 85–90% | Very good |
| East / West | 90°/270° | 80–85% | Good |
| ENE / WNW | 67°/293° | 65–75% | Marginal |
| NE / NW | 45°/315° | 55–65% | Generally not recommended |
| North | 0°/360° | 50–60% | Not recommended |
For context, a 4 kWp south-facing system in central England typically generates 3,400–4,200 kWh/year. The same system facing east or west generates roughly 2,900–3,700 kWh — lower, but still a substantial amount of electricity.
Output by tilt angle
Tilt matters less than orientation. The UK's optimal pitch is 30–40°, close to the UK's latitude (50–60°N) and conveniently near the pitch of most British houses.
| Tilt angle | South-facing output | Notes |
|---|---|---|
| 0° (flat) | 87–90% | Mount on A-frames at 10–15° |
| 15° | 95% | Good |
| 30–40° | 100% | Optimal — most UK roofs |
| 50° | 97% | Slightly less |
| 60° | 90–92% | Still decent |
| 90° (vertical) | 60–68% | Rare, wall-mounted only |
A roof at 20° versus 40° loses only 2–5% of output. The pitch matters far less than people expect. If your roof is anywhere from 15° to 50°, it's effectively fine.
Why south is best in the UK
The UK sits between 50° and 60° north latitude. Because of this, the sun stays in the southern half of the sky all year, and winter sunlight arrives at a low angle. A south-facing roof catches the most direct sunlight for the longest period, which is why it's the benchmark for maximum annual generation.
Real-world confirmation: a study of 26 residential systems across Yorkshire found that panels facing almost exactly due south produced the best results — 3,350–4,010 kWh annually from a 4 kWp setup.
East & west roofs (and split arrays)
An east or west-facing roof produces 80–85% of a south-facing system — lower, but far from useless. And there's a hidden advantage:
East-facing panels generate more in the morning; west-facing panels generate more in the evening. If you're home in the mornings or evenings, the generation may match your consumption better than a midday-peaking south system.
A split array — panels on both the east and west slopes — typically produces 80–85% of a south system, but spreads generation across the whole day. For households that use electricity morning and evening, this can improve self-consumption and battery utilisation enough to be worth more than the raw numbers suggest.
The payback impact is modest: if a south-facing system pays back in ~8 years, the same system facing east or west pays back in roughly 9–10 years. Still an excellent return.
North-facing roofs
North-facing panels produce only 50–65% of a south-facing system, and payback periods extend significantly. Most installers advise against them.
The exception: if you have exceptionally high electricity costs, no other roof space, and a shallow pitch, a north array might just about work — but it's rarely the right call. You'd almost always be better off looking at east/west options or a ground-mounted system instead.
Flat roofs
A flat roof (0–10°) loses around 10–15% versus an optimal angle, but has one big advantage: you can orient panels freely using A-frame mounting at 10–15°. That means you can point them due south regardless of the building's orientation.
Shading matters more than orientation
Here's the most important thing most guides skip: shading usually hurts more than a sub-optimal orientation.
A shadow across 10% of a panel can cut that panel's output by 30–50%. In a string-inverter system, one shaded panel can drag down an entire string's performance. Common culprits: trees, chimneys, satellite dishes, neighbouring buildings.
Rule of thumb: a south-east roof with zero shading will often outperform a perfect south roof with a morning-shading tree. Fix the shading (trim the tree, or use microinverters/optimisers) before worrying about a few degrees of orientation.
How to check your roof's direction
- Compass app on your phone — stand facing the slope and read the bearing (180° = south).
- Google Maps satellite view — your roof's orientation is visible from above; the top of the map is north.
- Installer survey — any reputable MCS installer will measure azimuth and pitch as part of their site survey and provide a PVGIS-based generation estimate.
Once you know your orientation, plug it into our calculator to see how many panels you need and what they'll save you.
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Calculate panels →FAQ
Is a south-east roof okay for solar?
Yes. A south-east (or south-west) roof produces 90–97% of a due-south system. The loss is small enough that shading and other factors usually matter more.
How much do I lose with an east-facing roof?
East or west-facing roofs produce 80–85% of a south-facing system. On a 4 kWp system, that's roughly 2,900–3,700 kWh/year instead of 3,400–4,200 kWh.
Can I put solar on a north-east roof?
North-east and north-west roofs produce only 55–65% of a south system and are generally not recommended. East/west or ground-mounted options are usually better.
Does a steeper roof hurt solar?
Not much. A 60° pitch still produces ~90% of optimal output. The pitch matters far less than orientation and shading.
Sources: MCS MIS 3002 yield estimates, PVGIS (European Commission), University of Strathclyde east-west array research, solarinfo.uk and iwantsolar.co.uk orientation data (2026). Figures verified August 2026. Actual output depends on your postcode, pitch, shading and system design.
Disclaimer: this guide is for general information only. Actual generation depends on your specific roof, location and shading — always get a site-specific estimate from an MCS-certified installer.