Which way should solar panels face?

South. Everyone knows that bit. What nobody tells you is how much you lose if your roof faces somewhere else, and for a lot of Hereford houses the answer is less than you would think.

We ran every direction and pitch through PVGIS, the EU’s solar data tool, for a 4kW system in Hereford. These are averages from satellite records between 2005 and 2023, so they are real Herefordshire weather, cloud and all.

Direction

A 4kW system on a roof pitched at 35 degrees, which is a common pitch round here:

Roof faces	Units a year	Compared with south
South	3,990	best
South-east	3,770	94%
South-west	3,750	94%
East	3,190	80%
West	3,160	79%
North-east	2,500	63%
North-west	2,470	62%
North	2,160	54%

So south-east or south-west costs you about 6%. That is close to nothing, and it is no reason to turn a job down.

East or west costs you about a fifth over a year. That sounds a lot until you look at when the power arrives, further down.

North on its own makes about half what south does at a normal pitch. On a shallow roof it is better: at 15 degrees a north slope makes 71% of the best figure. Still, a steep north slope is rarely worth it, and we will say so at the survey.

Pitch

For a south-facing roof in Hereford the best angle is 40 degrees, at 4,000 units a year on a 4kW system. Anything from 25 to 50 degrees lands within 3% of that, which covers most pitched roofs in the county.

Pitch	Units a year (south)	Compared with best
15 degrees	3,740	93%
25 degrees	3,910	98%
35 degrees	3,990	100%
40 degrees	4,000	best
50 degrees	3,950	99%
60 degrees	3,810	95%

You do not need a perfect roof. You need a roof without much shade on it.

East and west together

This is the one people underrate.

In June, an east or west roof in Hereford makes about 94% of what a south roof makes. In December it makes 43%. Around 60% of the yearly shortfall falls between October and March, the short days when the sun stays low in the south.

The timing matters too. In June:

• An east roof makes about 60% of its power before 1pm.
• A west roof makes about 38% of its power after 4pm, against 23% for a south roof.

Power you use in the house is worth what you would have paid for it, 26.32p a unit at the October to December 2026 price cap. Power you export earns 3p to 13p, depending on your tariff. So a west roof feeding the house while the kettle and the oven are on can be worth more than its lower total suggests. Our export payments guide has the rates.

A house with an east slope and a west slope also has two roof faces to use instead of one, so it can often take more panels than a single south slope would.

Flat roofs and walls

Flat roof: panels laid completely flat make 83% of the best figure. Tilted on frames at 10 to 15 degrees, they make 91% to 93%. Planning rules for flat roofs on houses are in our planning permission guide.

South-facing wall: 72% of the best figure. The planning rules for panels on house walls were relaxed in August 2026, so a sunny gable end is worth a look if the roof is no good.

What matters more than direction

Shade. One tree or a neighbour’s chimney across part of the array can cost you more than the difference between south and west. We look at that first, and fit optimisers where any panel catches shade. More on that in is my roof any good for solar?

The short version

• South is best, but south-east and south-west lose only about 6%.
• East or west loses about a fifth over the year, mostly in winter, and moves more of the power into the morning or the evening.
• North works on a shallow roof, and a steep north slope rarely does.
• Pitch matters far less than shade.

Send us a photo of your roof and tell us which way it faces. We will give you the figure for your house, and the survey is free.