Solar panels on a north-facing roof — is it still worth it?

How much electricity does a solar system produce on a north-facing roof?

The honest answer: less than on a south-facing roof — but more than many think. Yields by orientation and pitch: South 30–35° = 100% (reference). East/West 30° = 90–95%. North 20° = 70%. North 30° = 61%. North 40° = 50–55%. Flat north roof 7–10° = 75–80%.

What this means in practice: A 10 kWp system on an optimal south-facing roof produces approx. 10'000 kWh/year in Switzerland. The same system on a north-facing roof at 30° produces approx. 6'100 kWh/year. On a flat north roof (10°) it is approx. 7'500–8'000 kWh/year.

The key insight: The flatter the north-facing roof, the better the yield.

Why a north-facing roof is not as bad as you think

1. Diffuse light — the underestimated factor: In Switzerland, the sky is often overcast. On cloudy days, a north-facing installation produces as much as south-facing ones — because diffuse light comes from all directions. In the Plateau, where fog is common, this effect is significant.

2. Morning and evening sun in summer: In Swiss summer, the sun rises in the north-east and sets in the north-west. A north-facing roof receives direct sunlight in the morning and evening — exactly when self-consumption is often highest.

3. Cooler modules = higher efficiency: Modules on a north-facing roof heat up less. Since efficiency drops with heat, north-facing modules can produce almost as much as south-facing ones on hot summer days.

When does a north-facing roof make sense — and when not?

It makes sense when:

• ✅ The pitch is shallow (under 25°) — yield 70–80% of a south roof
• ✅ Self-consumption is high — those who use the electricity themselves benefit even from less production
• ✅ A battery storage system is in place — stores daytime electricity for the evening
• ✅ No south-facing surface is available — north roof as the only option
• ✅ The north roof is used in addition to a south surface — combination maximises total production
• ✅ An EV or heat pump is present — high self-consumption makes north installations viable
• ❌ The pitch is very steep (over 40°) — yield drops to 50–55%
• ❌ Additional shading is present — north roof + shading = very little electricity
• ❌ A south-facing surface is unused — cover south first, then check north

South and north roof combination — the best solution

If your house has a gable roof with south and north sides, the optimal strategy is often: cover both sides.

Advantages: More total production, more consistent production morning and evening, higher self-consumption, optimal daily coverage (north in morning/evening + south at midday).

Practical example Lucerne — 6 kWp south (30°) + 4 kWp north (30°): South roof approx. 6'000 kWh/year. North roof approx. 2'440 kWh/year. Total approx. 8'440 kWh/year. With storage approx. 5'500 kWh self-consumed = CHF 1'650 saved. The north roof contributes approx. 29% to total production — not ideal, but clearly positive.

What is the optimal pitch angle for a north-facing roof?

Rule of thumb: The flatter the better — with a lower limit of 7°. Yields by pitch: 7–10° = 75–80% (very good). 15–20° = 70–75% (good). 25–30° = 62–70% (acceptable). 35–40° = 55–62% (borderline). 45°+ = under 55% (not recommended).

Caution: Below 7° pitch there are self-cleaning problems — rainwater cannot drain well, leading to dirt build-up and reduced yield.

Which modules are particularly suited to north-facing roofs?

Good performance in diffuse light: Monocrystalline N-Type modules (TOPCon, HJT) produce better in overcast conditions and diffuse light than older PERC technology — particularly recommended for north-facing roofs.

Bifacial modules: On the north roof, bifacial modules can benefit from light reflected by roof tiles — but the additional yield is small and rarely justifies the extra cost.

Recommendation: Tier-1 manufacturers with TOPCon or HJT technology, at least 21% efficiency.

Is it still worth it financially? North-facing roof calculation example Zurich

Starting point: Single-family home Zurich, north roof 25°, 10 kWp. Annual production: approx. 6'100 kWh. Self-consumption 40% = 2'440 kWh. Feed-in: 3'660 kWh × CHF 0.08 = CHF 293.

Annual savings: Self-consumption 2'440 × CHF 0.30 = CHF 732. Feed-in CHF 293. Total CHF 1'025/year.

Investment after OTP and tax deduction: approx. CHF 12'300 net. Payback: approx. 12 years.

With battery storage: self-consumption rises to 65% → CHF 1'350/year. Comparison south roof: approx. CHF 1'500–1'700/year, payback 8–10 years. The north roof is viable — but less profitable than a south roof.

What to do with a shaded north-facing roof?

Shading is particularly critical on north-facing roofs. Solutions:

Module optimisers: Small devices mounted on each module that prevent a shaded module from limiting the whole system. Highly recommended for north-facing roofs with partial shading.

Micro-inverters: Each module has its own small inverter. Maximum independence from shading, but higher costs.

Smart module placement: An experienced installer can arrange modules to minimise shaded areas.