Solar Shading Loss Calculator
Will that tree or parapet shade your array? Winter shadow length, shaded hours and annual % energy loss.
One shaded panel can throttle an entire series string — shading is the most underestimated loss in rooftop solar. Enter the obstruction's height and distance: the tool computes the worst-case (winter solstice) shadow length, whether it reaches your array, and the estimated annual energy cost, with the minimum clear distance to design for.
Shadow length = height ÷ tan(sun altitude). Design rule: keep obstructions closer than their winter-noon shadow length away — or put shaded panels on their own optimizer/MPPT so one shadow can't throttle the whole string.
Engineering estimate from published standards and typical equipment data. Site conditions, equipment datasheets and measured data govern the real result — confirm with a qualified engineer.
Use the free Solar Shading Loss Calculator online — Will that tree or parapet shade your array? Winter shadow length, shaded hours and annual % energy loss. Runs instantly in your browser: no signup, no upload, mobile-friendly.
About Solar Shading Loss Calculator
One shaded panel can throttle an entire series string — shading is the most underestimated loss in rooftop solar. Enter the obstruction's height and distance: the tool computes the worst-case (winter solstice) shadow length, whether it reaches your array, and the estimated annual energy cost, with the minimum clear distance to design for.
How to use Solar Shading Loss Calculator
- 1Measure the obstruction's height above your array plane and its distance.
- 2Enter site latitude and what share of the array shares the affected string.
- 3Read shadow length, shaded hours and the estimated annual energy loss.
Why use Solar Shading Loss Calculator?
- ✓Worst-case (winter solstice) geometry — the day shadows are longest
- ✓String-aware: models how one shaded panel throttles a whole series string
- ✓Returns the minimum clear distance to design to
- ✓Two measurements (height, distance) replace a site-survey guess
Frequently asked questions
How far should solar panels be from a shading object?+
Farther than the object's winter-noon shadow: height ÷ tan(90° − latitude − 23.45°). In Delhi, that's about 1.5× the obstruction height; in London, nearly 4×. The calculator computes your exact minimum clear distance.
Why does a small shadow cause a big power loss?+
Panels in a string share one current path — a shadow on one panel chokes the current of every panel in that series string, much like a kink in a hose. A 5% shadow can cause a 30–50% string loss without electronics to isolate it.
Do optimizers or microinverters fix shading?+
They contain it: each panel (or pair) gets its own maximum-power tracking, so a shaded panel loses only its own output instead of dragging the string. Worth the premium on roofs with unavoidable chimneys, tanks or seasonal tree shade — not needed on clear roofs.
Is morning or evening shade as bad as midday shade?+
No. Power production is concentrated between roughly 9 am and 3 pm solar time — shade outside that window costs little. Midday shade in winter (low sun, long shadows, decent irradiance) is the case that hurts, which is why this tool models winter noon.
Embed Solar Shading Loss Calculator on your website
Want Solar Shading Loss Calculatoron your own site? Paste this snippet into any HTML page — it's free, with no API key or sign-up. The tool loads in an iframe and keeps working exactly as it does here.
<iframe src="https://tooljolt.com/tools/solar-shading-loss-calculator" width="100%" height="640" style="border:1px solid #e5e7eb;border-radius:12px;max-width:680px" title="Solar Shading Loss Calculator — ToolJolt" loading="lazy"></iframe>Related Energy tools
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