Quick Answer: In the UK, solar panels perform best facing south at a 30-35° angle, but southeast/southwest orientations lose only 3-4% efficiency. Even east/west setups produce 65-80% of optimal output, making most roof configurations viable for solar installation.
Many UK homeowners assume their roof is unsuitable for solar panels because it does not face perfectly south. In reality, most roofs across the UK can generate substantial solar electricity when correctly designed.
While due south at an appropriate tilt produces the highest annual output, east, west and even some north-facing roofs can still perform effectively depending on pitch, shading and system configuration.
To understand whether your roof is suitable, it helps to know how direction, tilt and UK-specific sunlight patterns affect solar performance.
Key Takeaways
- Due south (0° azimuth) delivers the highest annual solar generation in most UK regions.
- Roofs within approximately ±30° of south typically retain a high proportion of south-facing performance.
- East and west-facing systems are widely installed and remain technically viable.
- Typical UK solar generation ranges from 850 to 1,050 kWh per installed kWp per year depending on location.
- Shading can reduce output more significantly than moderate differences in orientation.
- Final performance depends on postcode, roof pitch, shading and system design.
Why Direction and Angle Matter for UK Solar Panels
The UK sits between 50° and 60° north latitude. Because of this:
- The sun remains in the southern half of the sky throughout the year.
- Winter sunlight arrives at a much lower angle.
- Summer days are long but the sun still travels across the southern sky.
- A significant share of UK solar radiation is diffuse due to cloud cover.
Unlike equatorial regions where panels may receive overhead sun, UK solar systems rely heavily on capturing lower-angle sunlight efficiently. This is why orientation and tilt influence annual energy yield.
Under typical conditions:
- Southern England may achieve around 950 to 1,050 kWh per kWp annually.
- Northern England typically sees 850 to 950 kWh per kWp.
- Northern Scotland may range between 750 and 900 kWh per kWp.
These figures assume reasonable orientation and minimal shading.
Best Direction for Your Solar Panels
South-facing installations deliver the highest annual energy yield in the UK. This isn’t just theory; it’s backed by solid research.
A study of 26 residential systems across Yorkshire found that panels facing almost exactly due south (-1° to be precise) produced the best results. These systems generated between 3,350-4,010 kWh annually from a 4kWp setup.
But what if your roof doesn’t face south?
| Direction | Typical Output Compared to South |
|---|---|
| South (optimal) | 100% |
| Southeast / Southwest (±30°) | 96–97% |
| East / West | 65–80% |
| North | 50–60% |
So, the good news is that panels facing southeast or southwest (within 30° of south) only lose about 3-4% efficiency. Even roofs that are up to 45° off south still perform well enough that other factors like shading often matter more.
Many UK homes have east-west roof orientations. Recent research from the University of Strathclyde shows these setups produce about 64-66% of what identical south-facing systems generate.
East-west systems have a hidden advantage, though. They spread electricity generation throughout the day, often better matching typical household usage patterns. Morning sun hits east-facing panels when you’re making breakfast, while evening sun hits west-facing panels when cooking dinner.
This timing advantage can boost self-consumption rates, making these setups more valuable than raw production numbers suggest.
North-facing roofs are generally the least suitable, producing only 50-60% of what south-facing panels would generate. They’re usually only worth considering if you have exceptionally high electricity costs and no other roof space available.
Understanding Azimuth in UK Solar Modelling
Solar panel direction is measured using azimuth.
In UK solar modelling tools such as PVGIS and SAP:
- 0° azimuth = Due South
- −90° = Due East
- +90° = Due West
- ±180° = Due North
South-facing systems are used as the benchmark because they receive the most balanced sunlight across all seasons.
When installers assess your roof, they measure its azimuth to estimate annual energy production accurately.
South-Facing Solar Panels (0° Azimuth)
South-facing roofs receive the most consistent annual solar irradiance in the UK.
At common roof pitches between 30° and 40°:
- They capture strong summer sunlight.
- They perform well during spring and autumn.
- They maintain better winter performance than other orientations.
A well-positioned 4 kWp south-facing system in much of England typically generates between 3,400 and 4,200 kWh per year, depending on local conditions.
This orientation provides the highest annual yield in most UK postcodes.
South-East and South-West (Within ±30° of South)
Roofs within approximately 30° of due south remain highly effective.
Although annual generation may be slightly lower than perfect south alignment:
- South-east systems produce more energy in the morning.
- South-west systems produce more energy later in the afternoon.
- Annual losses compared to south are typically modest at standard roof pitches.
For many households, these orientations remain excellent choices.
East-Facing Solar Panels (−90° Azimuth)
East-facing panels receive direct sunlight primarily in the morning hours.
Compared to south-facing systems:
- Total annual output is lower.
- Winter generation is reduced.
- Morning production is strong during brighter months.
East-facing systems are common in UK homes with north-south roof ridges. They can suit households that use more electricity earlier in the day.
West-Facing Solar Panels (+90° Azimuth)
West-facing panels receive stronger sunlight in the afternoon and early evening.
Although annual generation is typically lower than south-facing systems:
- Afternoon production can better match evening electricity demand.
- Generation extends later into the day.
- Performance remains technically viable across most UK regions.
West-facing systems are frequently paired with battery storage to maximise self-consumption.
East–West Split Roof Systems
Many UK properties have one east-facing and one west-facing roof slope.
Instead of choosing one side, installers often split panels across both.
This approach:
- Spreads electricity production across more hours of the day.
- Reduces midday export spikes.
- Aligns better with typical household demand patterns.
While total annual output may be lower than a purely south-facing array of the same size, east–west systems remain a practical and widely used solution.
North-Facing Solar Panels (±180° Azimuth)
North-facing roofs receive the least direct sunlight in the UK, particularly during winter when the sun stays low in the southern sky.
At standard roof pitches between 30° and 40°:
- Annual irradiance is significantly lower.
- Winter output is limited.
- Performance depends heavily on pitch and shading.
North-facing systems are generally only recommended after detailed modelling confirms acceptable generation levels.
Optimal Tilt Angles Across the UK
The ideal tilt angle varies slightly based on where you are in the UK:
| Region | Latitude | Optimal Tilt |
|---|---|---|
| South England | 50–52°N | 30–35° |
| Midlands & Northern England | 53–55°N | 35–40° |
| Scotland | 56–58°N | 40–45° |
Most UK homes have roof pitches between 30-45°, putting them naturally close to optimal angles.
Steeper angles (40-45°) capture more winter sun when it sits lower in the sky. If winter electricity use is high in your home, perhaps for heating, a slightly steeper angle might be beneficial.
Shallower angles (20-30°) favour summer production. For households with higher summer electricity use, perhaps for cooling or with more occupants during school holidays, a flatter installation could work better.
The Impact of Shading
Shading can reduce solar output more significantly than moderate differences in roof orientation. Even partial shading on a single panel can lower the performance of the entire system, particularly in string inverter setups where panels operate in series.
Common sources of shading include trees, chimneys, dormers, neighbouring buildings and rooftop equipment. Because the sun’s position changes throughout the year, areas that appear unshaded in summer may experience shadowing in winter.
For accurate performance estimates, a professional shading assessment is recommended before installation.
Roof Type Considerations
Pitched Roofs
Most UK pitched roofs are naturally well suited to solar panels because their angles typically fall within the optimal 30° to 45° range. This means additional tilt adjustment is rarely required.
Under permitted development rules in England, panels must not protrude more than 0.2 metres beyond the roof plane. Modern mounting systems are designed to comply with this while maintaining strong performance.
Flat Roofs
Flat roofs require a different installation method because they do not provide a natural tilt angle. Solar panels are therefore mounted on angled frames, typically set between 10° and 15°.
This moderate tilt helps:
- Improve rainwater runoff
- Reduce wind uplift forces
- Maintain compliance with planning height restrictions
Although this angle is shallower than the optimal tilt for maximum annual yield, it provides a practical balance between structural stability and energy performance.
Since December 2023, permitted development rules allow solar panels on flat roofs to extend up to 0.6 metres above the roof surface in most cases without requiring planning permission. This change gives installers greater flexibility when designing flat roof systems.
Practical Steps to Optimise Your Solar Setup
Not sure which way your roof faces? Here are some simple methods to check:
- Use a compass app on your smartphone while standing beside your house
- Check Google Maps satellite view of your property
- Look at your property deeds, which often include directional information
Remember that magnetic north differs slightly from true north in the UK. Allow for a few degrees of magnetic declination when using a compass.
Shading is often more important than perfect alignment. A small amount of shade can reduce output by far more than a suboptimal angle. Common shading culprits include:
- Nearby trees (especially those that will grow taller)
- Neighbouring buildings
- Chimneys
- Satellite dishes
- Roof vents
Walk around your property at different times of day to spot potential shading issues. Winter sun casts longer shadows, so what seems clear in summer might be shaded in winter.
Sometimes, the perfect angle and direction must be balanced against available space. A slightly less optimal orientation that accommodates more panels may generate more total energy than a perfectly oriented, smaller system.
Consider battery storage for east or west-facing panels. Batteries allow you to store energy produced during the day for use in the evening, increasing self-consumption rates significantly.
Explore smart export tariffs. Some UK energy companies now offer time-of-use export tariffs that pay more for electricity exported at peak times. This can make west-facing panels more valuable as they generate power later in the day when demand is higher.
Financial Considerations
Financial return depends on system size, electricity usage patterns, export tariffs, battery storage and installation quality. While orientation affects total generation, savings are largely influenced by how much of that electricity you use within the property.
Great News: Solar panel installations benefit from 0% VAT until 31 March 2027. After this date, the rate will return to 5%, offering substantial savings compared with the standard 20% VAT.
Conclusion
The science is clear: south-facing panels at 30-35° tilt will maximise your solar generation in most UK locations. However, the real-world message is more forgiving. Your existing roof orientation and pitch are likely already good enough for excellent performance without costly modifications.
Remember that shading, system quality, and installation expertise often impact performance more than small deviations from “perfect” positioning. Ready to find out exactly how much solar potential your roof has? Contact our expert solar assessment team for a free, no-obligation property evaluation and let the sunshine pay your bills.
FAQ
Can solar panels work effectively if not facing south?
Yes, panels facing southeast or southwest typically lose only 3-5% efficiency compared to south-facing installations. East and west-facing panels still generate about 65-80% of a south-facing system’s output, making them viable options, especially with battery storage.
Does the angle of solar panels matter during the winter months?
Yes, steeper angles (40-45°) perform better in winter as they capture more of the low winter sun. If winter generation is particularly important to you, consider a slightly steeper tilt than the standard 30-35° if your roof allows it.
Should I install solar panels on my east/west-facing roof?
Absolutely. East/west installations still generate substantial power and offer the advantage of spreading generation throughout the day. This often better matches household consumption patterns and can improve self-consumption rates.
How much efficiency do I lose with a non-optimal panel angle?
Very little. Research shows that even a 10° deviation from the optimal tilt angle typically reduces annual yield by only 2-4%. Most standard UK roof pitches will perform quite well without modification.
What’s more important: the right direction or avoiding shade?
Avoiding shade is far more critical. Even minimal shading can reduce panel output dramatically, whereas a suboptimal direction might reduce efficiency by just 5-10%. Always prioritise unshaded areas over perfect orientation.