SolarSums

Sun path and panel angle

Drag through the year and the day to see where the sun sits over your home. Then tilt and turn the roof to see how much solar output each angle gets.

Showing London until you enter a postcode.

Where the sun is

Sun path diagram seen from above. The centre is straight overhead, the outer ring is the horizon, north is at the top. Drag along the arc to change the time. NESW 60°30°

Selected day Midsummer, equinox, midwinter Way the roof faces

Sun height
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Sun direction
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Sunrise
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Sunset
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Day length
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Highest at noon
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Your roof

Compass. Drag the arrow to set which way the roof faces. NESW Side view of the panel. Drag the panel's top edge to change the tilt. The yellow line is the sun at the chosen time.

Yearly output at this angle

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Sun on the panel right now: –

How this works

The sun's position comes from the NOAA solar equations, worked out in your browser, so dragging is instant. Times are UK clock time, with British Summer Time where it applies. Sunrise and sunset allow for the bending of light near the horizon.

Yearly output comes from PVGIS, the EU Joint Research Centre's solar database. We fetch 27 roof angles and directions once for your area, then fill in the angles in between. Output is per kWp of panels, before shading from trees or nearby buildings. East and west faces are treated as equal. Nearby postcodes within about 10 km share one set of figures.

Ready to see whether panels pay back? Open the calculator and use the tilt and direction you found here.