Solar Panel Cleaning: Does It Actually Improve Efficiency?

Short answer: yes, meaningfully — dirty panels can lose a real percentage of their output, not just a cosmetic difference.

How Much Efficiency Is Actually Lost?

Buildup from dust, pollen, and bird droppings can block enough sunlight to reduce panel output noticeably, especially after a dry summer with no rain to naturally rinse panels off.

Why Calgary's Climate Makes This Worse

Dry periods between rainfall, combined with wind-blown dust (see our chinook winds post), mean Calgary panels accumulate grime faster than in wetter climates where rain provides more natural cleaning.

What Cleaning Actually Involves

Soft brushes and purified water — no abrasive tools, no high pressure, and nothing that risks scratching the panel surface or affecting the seal.

Is It Worth the Cost?

For most residential systems, an annual or biannual clean pays for itself through recovered efficiency, especially for panels that go a full season without significant rain.