The best place for solar panels in a UK home is a south-facing roof with a pitch of around 30-40 degrees, as this orientation maximises annual energy generation. According to the Energy Saving Trust, a south-facing roof in the UK can produce nearly 1,000 kWh more per year than an east-west facing system of the same size (Energy Saving Trust, 2026).
The answer depends on your roof’s orientation, pitch, and shading. South-facing roofs capture the most sunlight across the day. East- and west-facing roofs still work well, producing roughly 80-85% of the output of a south-facing system. North-facing roofs are generally not recommended, as they can cut generation by up to 30-40%. Shading from chimneys, trees, or neighbouring buildings can also significantly reduce performance, even on an otherwise ideal roof.
South-facing roofs deliver the highest output
A south-facing roof at a 30-40 degree pitch receives direct sunlight for the longest period each day, maximising kWh generation. The Energy Saving Trust states that a typical 3.5kWp south-facing system in the UK can generate around 3,000 kWh per year (Energy Saving Trust, 2026). This orientation works best for homes aiming to offset a large portion of their annual electricity use, which averages 2,700 kWh for a typical three-bedroom house according to Ofgem (Ofgem, 2026).
East-west roofs are a strong alternative
East- and west-facing roofs generate less total energy but spread production across morning and afternoon hours. This can be beneficial if you use more electricity in the morning or late afternoon. The Energy Saving Trust notes that an east-west system produces roughly 80-85% of the output of a south-facing array of the same size (Energy Saving Trust, 2026). For a 3.5kWp system, this means around 2,400-2,550 kWh annually, still enough to cover a significant chunk of household demand.
Flat roofs and ground mounts are viable options
If your roof is flat, panels can be mounted on angled frames, typically tilted to 10-15 degrees to prevent self-shading. This reduces output slightly but is still practical. Ground-mounted panels are an alternative if you have garden space, offering flexibility to orient them due south at the optimal pitch. The Microgeneration Certification Scheme (MCS) requires all installations to meet specific standards for safety and performance (MCS, 2026). Avoid north-facing roofs unless no other option exists, as generation drops significantly.
A worked example
A typical 3.5kWp solar panel system on a south-facing roof of a 1930s semi-detached house in Manchester costs around £7,000 after the 0% VAT saving (in place until March 2027). This system generates roughly 3,000 kWh per year according to the Energy Saving Trust. With a household using 2,700 kWh annually, you could save approximately £640 per year on electricity bills at current price cap rates of 24.5p per kWh. The payback period is around 11 years, and over a 25-year system lifetime the total savings reach roughly £16,000. If your roof faces east-west instead, you would generate about 2,550 kWh per year, saving around £480 annually with a payback period of 14 to 15 years.
| Item | Figure |
|---|---|
| Upfront cost after grants | £7,000 |
| Yearly savings | £640 |
| Payback period | 11 years |
| 25-year lifetime savings | £16,000 |
What homeowners often get wrong
The most common mistake is assuming any roof will generate the same amount of electricity. Three misconceptions frequently lead to poor performance or wasted money.
- Thinking north-facing roofs are worthwhile A north-facing roof can cut generation by up to 40% compared to a south-facing system, meaning a 3.5kWp setup might produce only 1,800 kWh per year. This reduces annual savings to roughly £380 and extends the payback period beyond 18 years, often making the investment uneconomical.
- Ignoring shading from nearby trees or chimneys Even a small shadow covering 10% of a panel can reduce total system output by up to 30% because panels are wired in series. This could cost you £190 per year in lost savings and may void your warranty if the installer does not account for shading in the design.
- Believing east-west roofs are useless Many homeowners dismiss east-west roofs as poor options, but they still generate 80-85% of a south-facing system’s output. A 3.5kWp east-west setup in the UK produces around 2,550 kWh per year, saving roughly £480 annually with a payback period of 14 to 15 years.
Quick reference
- A south-facing roof at 30-40 degrees pitch generates around 3,000 kWh per year for a typical 3.5kWp system in the UK.
- East-west facing roofs produce approximately 80-85% of the output of a south-facing system. That makes them a viable option.
- You can check your roof’s suitability using the Energy Saving Trust’s solar calculator or by booking a site survey from an MCS-certified installer.
- Installing solar panels reduces your annual electricity bill by roughly £640 for a south-facing 3.5kWp system at current price cap rates.
- Shading from chimneys, trees, or neighbouring buildings can cut generation by up to 30% even on an otherwise ideal roof orientation.
Frequently Asked Questions
South-facing is best, producing nearly 1,000 kWh more per year than east-west systems. The Energy Saving Trust confirms this orientation maximises annual output.
Yes, they produce roughly 80-85% of a south-facing system's output. They spread generation across morning and afternoon hours, according to the Energy Saving Trust.
A pitch of 30-40 degrees is ideal for maximising solar generation. The Energy Saving Trust notes this angle captures the most sunlight throughout the year.
