For Solar Installers & Homeowners

Instant Rooftop Solar Potential

Visualize roof shadows to optimize solar panel placement. See how obstructions affect sun exposure throughout the year.

Check My Roof Sunniest Cities

How Shadows Affect Solar Output

Partial Shading = Big Loss

Even small shadows on one cell can reduce entire panel output by 30-50% due to how panels are wired.

Peak Hours Matter Most

Solar production is highest between 9am-3pm. Shadows during these hours have the biggest impact.

Seasonal Changes

Shadow patterns change dramatically between summer and winter. Check both seasons before installing.

What to Check Before Installing

Use SunMap to analyze these potential shadow sources on your roof.

Neighboring Buildings

Tall buildings to the south (Northern Hemisphere) can cast long shadows, especially in winter when the sun is low. Check shadow patterns in December.

Trees

Trees can block significant sunlight. Remember that deciduous trees lose leaves in winter but evergreens block light year-round.

Chimneys & Vents

Roof obstructions like chimneys cast shadows that move throughout the day. Plan panel placement to avoid these shadow paths.

Roof Orientation

South-facing roofs (Northern Hemisphere) receive the most direct sunlight. East/west roofs can work but with ~10-15% less production.

Best Cities for Solar

Cities with the most clear days offer the highest solar potential.

Samarinda

Indonesia

Clear days/year:299

Peak sun altitude:67°

Pontianak

Indonesia

Clear days/year:299

Peak sun altitude:67°

View all sunniest cities

Frequently Asked Questions

How do I check if my roof is suitable for solar?

Use SunMap to view your roof in 3D and simulate shadows throughout the year. Check for obstructions from chimneys, nearby buildings, and trees. Roofs with unshaded south-facing sections are ideal.

How much do shadows reduce solar output?

Even partial shading can significantly reduce efficiency. A shadow on just one cell can reduce output by 30-50%. Use SunMap to identify which roof areas receive consistent sunlight between 9am-3pm.

What time of day is best for solar production?

Peak solar production occurs when the sun is highest (around solar noon) and when days are longest (summer solstice). SunMap shows sun altitude and day length to help plan optimal panel placement.

Ready to Go Solar?

Check your roof's solar potential for free. See exactly where shadows fall.

Analyze My Roof