South-facing at the perfect tilt is the textbook ideal. Most real roofs aren't that — and it usually matters less than people fear.
South-facing is ideal in the Northern Hemisphere, but the penalty for off-axis is gradual
A due-south orientation captures the most sun over a full day in most of the U.S., but east- or west-facing roofs typically lose only a modest percentage compared to true south — not a dramatic falloff. North-facing is the real weak point, meaningfully underperforming the other three directions, though even that isn't automatically a dealbreaker depending on the rest of the roof.
Tilt angle matters less than orientation for most installations
The ideal tilt roughly matches your latitude for annual production, but most residential roof pitches (typically 15-40 degrees) perform reasonably well without needing an exact match — see the roof angle calculator for how your specific roof's tilt compares to ideal.
East-west split arrays are a legitimate strategy, not a compromise
Splitting panels across east- and west-facing roof sections instead of concentrating everything on a smaller south-facing area can produce a flatter daily production curve — more power in the morning and evening, less at midday peak — which sometimes aligns better with actual household usage patterns or time-of-use rate structures.
Shading usually matters more than orientation
A well-oriented roof with significant shading from trees or nearby structures can underperform a moderately-oriented roof with a clear view of the sky — see our shading loss guide for why shade often deserves more attention than orientation in practice.
Frequently asked questions
Is a west-facing roof a bad candidate for solar?
Not necessarily — it typically produces meaningfully less than true south but still performs reasonably well, and can actually align nicely with afternoon/evening usage patterns or certain time-of-use rate structures.
Should I avoid solar entirely if my roof only has north-facing space?
It depends on the rest of the situation — north-facing is the weakest orientation, but a ground-mount alternative, a different section of roof, or simply accepting reduced production from the north-facing section are all options worth evaluating before ruling out solar entirely.