How much does orientation really Matter?

This is one of the most common concerns we hear during our consultations in Luxembourg:
“My roof isn’t facing due south… is it still worth installing solar panels?”

It’s a fair question and the good news is that in most cases, the answer is yes.
Even with a less-than-perfect orientation or inclination, a photovoltaic system can still be profitable, efficient, and relevant.

In this article, we explain transparently how your roof’s orientation (azimuth) and tilt angle really impact solar production and why this is often not a dealbreaker for your project.

Ideal orientation: facing south, but not essential

For solar panels in the northern hemisphere including Luxembourg the ideal orientation is facing due south. This positioning allows the panels to capture the maximum amount of sunlight throughout the day, especially around solar noon when the sun is highest in the sky.

However, studies show that even east or west-facing panels can still produce around 80 to 85% of the energy of a south-facing system, depending on the tilt and shading conditions. According to the National Renewable Energy Laboratory (NREL) and IRENA, the impact of orientation becomes less critical when energy demand matches production curves for example, west-facing systems can be ideal for households with higher consumption in the late afternoon. So, while south is optimal, solar remains a viable investment even when your roof faces east or west.

What if my roof faces east or west?

This type of setup is actually very common in Luxembourg, especially with dual-pitch roofs.

By installing panels on both the east and west sides, solar production is naturally spread between the morning and the afternoon. The result?

Better alignment with your actual consumption
Less excess energy fed into the grid
A return on investment often comparable to a south-facing roof

Even though the annual output may be slightly lower (typically 85 to 90% of a south-facing setup), the investment remains very attractive especially with local subsidies available.

Roof inclination: how much does it matter?

To maximize solar production in Luxembourg, the ideal roof pitch is between 25° and 35°.
But here too, the tolerance range is wide:

Inclinaison du toit	Perte estimée
25–35°	Optimale
15–25°	~5 %
10°	~8 %
0° (toit plat)	~10–12 %

At Ecoclima, we regularly install solar panels on both flat and steep roofs.
We adapt every system to maximize energy production, regardless of the roof’s shape or slope.

What about north-facing roofs?

This is the least favorable case. A full north-facing roof can reduce solar production by 25 to 35%.

That said, in certain specific situations, a north-facing installation can still make sense:

If the other roof sections are unusable (due to shading, building regulations, or fragile materials)
If an inverted mounting structure is technically feasible
If you’re eligible for generous subsidies or financial incentives
Or if you have a large north-facing roof and your energy usage is well distributed throughout the day

In any case, we carry out a free and personalized assessment to evaluate your roof’s actual potential.

How much energy will I produce based on my roof orientation?

Even with a non-optimal orientation, your solar system can still be both efficient and cost-effective. East- or west-facing panels typically produce around 80 to 90% of what a south-facing system would often enough to make the investment worthwhile, especially with rising energy prices and local incentives in Luxembourg.

Here’s a quick overview of estimated annual production relative to a perfectly south-facing system (considered 100%):

Orientation	Estimated Production
South	91-100 %
Southeast / Southwest	89–97 %
East / West	57–84 %
North	23–84 %

Even if your roof isn’t perfectly south-facing, it can still host a highly efficient solar system especially when factoring in the tilt angle.

The inclination of your roof plays a major role in determining energy yield. A flat roof, even when facing north, can still provide good production thanks to optimal panel placement. However, as the tilt angle increases, losses become more significant particularly for roofs facing non-optimal directions. Conversely, a south-facing roof will remain productive even with a steeper pitch, as the orientation compensates for part of the incline loss.

What we offer at Ecoclima

Our goal isn’t just to install panels. It’s to design a solar system that helps you produce energy effectively, with no unpleasant surprises.

Tailored technical assessment
Realistic estimation of energy output and return on investment
Full management of administrative steps with the Commune and Creos
Assistance with grant and subsidy applications
Clean, local, and aesthetically integrated installation

Based in Luxembourg, Ecoclima has extensive experience designing and installing solar systems adapted to all roof types and orientations including flat roofs, steep slopes, and east-west or non-south-facing surfaces. With over 500 installations completed across the country, our in-house team ensures each project is technically optimized, visually discreet, and tailored to deliver maximum energy performance, regardless of your roof’s layout. We’re happy to provide you with a free quote and a detailed assessment of your roof’s solar potential.