Solar Panels on an East-West Roof: The Real Story
If your roof faces east-west rather than south, you have probably been told that solar panels are not worth installing. This is one of the most persistent myths in the solar industry, and it is simply wrong. East-west solar arrays are installed across the UK every day, and the financial returns are excellent. Here is the data that proves it.
East-West vs South-Facing: The Numbers
A south-facing roof at the optimal 30-35 degree pitch in the North East will generate approximately 950-1,050 kWh per kWp per year. An east-west split array on the same property typically generates 800-900 kWh per kWp per year. That is a reduction of approximately 15-20%, not the 40-50% that some people assume.
However, the raw generation figure does not tell the whole story. An east-west array has a fundamentally different generation profile that can actually be more valuable for many households.
Why East-West Can Be Better for Self-Consumption
A south-facing array produces a sharp peak of generation around midday. If you are at work during the day, most of this peak is exported to the grid at low export tariff rates. An east-west array produces a flatter, wider generation curve: the east-facing panels generate more in the morning, and the west-facing panels generate more in the afternoon and early evening. This broader profile better matches the typical household consumption pattern, with higher generation during breakfast and tea-time when you are actually using electricity.
In practice, this means east-west arrays often achieve higher self-consumption rates than south-facing arrays of the same size. If you add battery storage, the difference becomes even smaller because the battery captures surplus generation regardless of when it occurs.
More Panels, More Total Generation
East-west roofs often provide more usable roof area than south-facing alternatives. On a typical UK house, a south-facing roof offers one side for panels. An east-west roof offers both sides. Even though each panel generates slightly less than it would facing south, the ability to install significantly more panels means the total annual generation from an east-west system is often higher than what could be achieved on the south-facing side alone.
We regularly install 20-30 panels across east-west roofs where a south-facing arrangement might only accommodate 12-15 panels. The total system output is substantially higher despite each individual panel producing slightly less.
Real Installation Example
One of our recent installations demonstrates this perfectly. We installed 25 Jinko Tiger Neo 430W all-black panels on an east-west roof, creating a 10.75kW system paired with a Tesla Powerwall. The system generates over 9,000 kWh per year, and the customer's self-consumption rate with the Powerwall exceeds 80%. The homeowner's electricity bill has dropped by over 75% compared to pre-solar levels. This would not have been possible with a smaller south-facing array.
Financial Return on East-West Systems
Taking a typical example: a 10kW east-west system costing approximately £11,000 (at 0% VAT) generating 8,500 kWh per year with 45% self-consumption (no battery) saves approximately £1,200 per year. With a battery pushing self-consumption to 80%, savings rise to approximately £1,800 per year. The payback period is 6-7 years with battery or 8-9 years without, which is comparable to south-facing installations of similar cost.
When Is East-West Not Suitable?
The only situations where we advise against east-west installations are when there is significant shading on one face (for example, tall trees to the east blocking morning sun), when the roof pitch is very steep (over 45 degrees), which exaggerates the orientation penalty, or when roof space is so limited that only a handful of panels can be installed. In these cases, concentrating panels on the better-performing face may make more sense.
Get an East-West Assessment
If you have an east-west roof and have been told solar is not worth it, get a second opinion. Contact ALPS Electrical for a free roof survey. We will model the expected generation for your specific roof using professional design software and show you exactly what an east-west system will deliver. The numbers speak for themselves.