The best angle for solar panels in the UK

The angle of your solar panels determines how directly sunlight hits them. When sunlight strikes a panel at 90 degrees, the panel captures the maximum energy. When sunlight hits at a shallow angle, much of the energy reflects off the surface or passes through without being absorbed.

In the UK, the sun is never directly overhead. It reaches its highest point at midday in June, when it sits between 55 and 62 degrees above the horizon depending on your latitude. In December, the midday sun barely reaches 15 degrees. Your panel angle needs to balance these extremes across the year.

The good news is that solar panels are forgiving. A panel tilted between 30 and 40 degrees and facing south will produce within 5 per cent of its maximum possible output. You do not need to hit the perfect angle to get good results.

The ideal panel angle in the UK ranges from 30 to 40 degrees depending on how far north you are. Further north, the sun sits lower, so panels benefit from a steeper angle. Further south, a shallower angle captures more of the high summer sun.

London and the South East: 30 to 35 degrees is optimal. Most existing roofs in this range already work well without adjustment.

South West (Bristol, Exeter, Plymouth): 32 to 36 degrees. The South West gets the highest irradiance in England, so getting the angle right pays off.

Midlands (Birmingham, Nottingham, Leicester): 33 to 37 degrees. The middle of the country sits in the middle of the angle range.

North West (Manchester, Liverpool, Preston): 35 to 38 degrees. Slightly steeper to capture the lower winter sun.

Yorkshire and North East (Leeds, Newcastle): 35 to 39 degrees. Similar to the North West, with marginally steeper optimal angles.

Scotland (Glasgow, Edinburgh, Aberdeen): 37 to 40 degrees. The furthest north and lowest sun means the steepest optimal tilt.

Most UK roofs are pitched between 30 and 45 degrees. If yours falls in that range and faces south, you are already in the sweet spot. You do not need to do anything special.

A roof at 20 degrees or flatter will produce about 8 to 12 per cent less than the optimal angle. That is a modest loss. For flat roofs, installers use mounting frames to tilt the panels at 20 to 30 degrees, which captures most of the available energy while keeping the array wind-resistant.

A roof steeper than 45 degrees loses about 5 to 10 per cent compared to optimal. Steeper roofs also shed snow and dirt better, which can recover some of the loss in practice. Very steep roofs above 60 degrees lose 15 to 20 per cent but are rare on UK housing.

The bottom line: if your roof is between 25 and 45 degrees, do not worry about the angle. Focus on direction and shading instead. Those factors have a bigger impact than a few degrees of tilt.

In the UK, the direction your panels face has a bigger impact on output than the angle. A south-facing roof is the gold standard, receiving sun throughout the day. South-facing panels produce 100 per cent of their potential output.

East or west-facing roofs produce 75 to 85 per cent of south-facing output. East-facing roofs generate more in the morning. West-facing generates more in the afternoon and evening. If you use more electricity in the afternoon, a west-facing roof can be more useful despite the lower total.

South-east or south-west facing roofs produce 90 to 95 per cent of south-facing output. These are excellent alternatives when a true south face is not available.

North-facing roofs produce only 50 to 60 per cent of south-facing output in the UK. They are generally not recommended for solar installation, though modern panels and optimisers can make them viable in exceptional cases.

A fixed panel angle is a compromise between summer and winter output. A shallower angle (25 to 30 degrees) maximises summer generation, when the sun is high and days are long. A steeper angle (40 to 45 degrees) maximises winter generation, when the sun is low and days are short.

Most UK systems are sized for summer output, because that is when generation is highest and electricity demand for lighting and heating is lowest. The standard 30 to 35 degree tilt favours summer performance, which is the right choice for most households.

If you heat with electricity or a heat pump, winter output matters more. A steeper angle of 38 to 42 degrees will produce more in December and January, at the cost of slightly lower summer peaks. This trade-off suits households whose demand peaks in winter.

Adjustable mounting systems let you change the angle seasonally. These are more common on ground-mounted arrays than roof-mounted ones. The extra output rarely justifies the cost and effort for a domestic roof system.

You can estimate your roof angle from the ground, but measuring it directly is more reliable. The WattSnap scanner uses your phone's motion sensors to read the direction and tilt you aim it at.

Open the scanner on your phone and aim the camera the way your roof faces, tilted to match its pitch: the camera stands in for the panel. The app reads the tilt in degrees and the compass direction, then calculates your expected solar output using the PVGIS satellite irradiance database.

This gives you a real number based on your actual roof, not a regional average. You can test east versus west, and trace the skyline to see how much nearby buildings and trees cost you over a year. Try it before you talk to an installer.