A 30–50% drop in winter generation surprises almost every new solar owner in North India. Part of it is physics you cannot change — but part of it is dust, angle and dirt that you can.
Causes you cannot change
- Shorter days — fewer sunshine hours
- Lower sun angle — panels receive less direct irradiance
- Fog, haze and cold spells — common across UP and Delhi NCR in December–January
Causes you CAN fix
- Dust — winter is dry and dusty; uncleaned panels lose significant output
- Bird droppings and leaves — block individual cells and can shut down a whole string
- Horizontal panel tilt — steeper tilt suits winter sun and helps dust self-cleaning
- Shade — low winter sun means shadows travel much further across the roof
What actually helps
Clean panels more often in winter (every 2–3 weeks in dusty areas), check the app for strings that underperform, and compare generation with the same period last year rather than with summer. If the drop is much steeper than the season explains, a fault — not the weather — is likely.
Frequently asked questions
Is low winter generation a fault?
Not by itself — 30–40% lower output in peak winter is normal. A sharper drop, or one string far below the others in the app, points to shade, dirt or a real fault worth checking.
Need a solar inverter repaired?
Share your inverter brand, model and error code — our technicians will guide you and share an estimate before any repair starts.