Solar Panels on an East-Facing Roof: Worth It?

A south-facing roof is optimal, but east-facing is far from poor:

Output comparison for a 4kW system: - South-facing: 4,000 kWh/year (100%) - South-east: 3,800 kWh/year (95%) - East-facing: 3,200–3,400 kWh/year (80–85%) - North-east: 2,500 kWh/year (62%) - North: 2,200 kWh/year (55%)

The 15–20% reduction from south to east is significant, but not enough to undermine the financial case. You still generate enough to save hundreds of pounds per year and achieve payback well within the panel lifespan.

Financial comparison (4kW, no battery): - South-facing savings: £700–£900/year, payback 8–12 years - East-facing savings: £550–£700/year, payback 10–14 years - Difference: £150–£200/year, 2 extra years to payback

Source: PVGIS orientation data for UK latitudes.

East-facing panels have one advantage over south-facing: they generate more in the morning.

An east-facing array starts producing earlier in the day as the sun rises in the east. Peak generation occurs between 8am and noon, then drops off in the afternoon as the sun moves south and west.

This is actually better for some households: - Morning routines: shower, breakfast, dishwasher, washing machine — heavy usage aligns with peak generation - Households that leave for work by 9am capture the most valuable generation before they leave - Combined with a west-facing array on the opposite slope, east panels create an extended generation window across the full day

South-facing panels peak at midday — which is ideal overall but misses the morning consumption peak that many households have.

Source: Energy Saving Trust consumption patterns research.

If your roof has both east and west slopes (common on UK homes), installing panels on both sides creates an east-west split system. This is often better than east-only:

East-west split advantages: - Generation spread across the full day (morning east + afternoon west) - Flatter output curve matches household consumption better - Can fit more total panels (using both roof slopes) - Combined output: approximately 85% of south-facing per panel, but potentially more total kWh if you install more panels

Works best with micro-inverters: Each panel operates independently, so east panels don't drag down west panels. This is the ideal inverter choice for east-west systems.

Example: 5kW east-west split (12 panels total, 6 east + 6 west): - Annual generation: ~4,300 kWh (85% of 5,000 kWh south-facing) - Annual savings: £700–£850 - More than a 4kW south-facing system that only fits 10 panels

Source: MCS system design guidance.

Install now. Waiting for a south-facing roof means missing years of savings. The maths:

Install now (east-facing): - Year 1 savings: £600 - 25-year total savings: £15,000 - Minus installation cost: £6,750 - Net profit: £8,250

Wait 5 years, then install on a south-facing roof: - 5 years of zero savings: £0 - Year 6–25 savings (south): £16,000 - Minus installation cost (likely higher in 5 years): £8,000 - Net profit: £8,000

The east-facing system installed today produces a similar or better 25-year return than waiting for a south-facing roof — because you start saving immediately.

Electricity prices are also likely to rise, which benefits earlier installation.

Source: Calculation based on Ofgem Q1 2026 rates with 3% annual price inflation assumption.