Should you wash your solar panels?

The post is a simple real-world test of whether washing solar panels pays off. The author cleaned a home array, compared production before and after, and concluded the gain was modest enough that regular paid cleaning probably does not pencil out for many households. That sparked two useful lines of discussion. First, people with lived experience said the result is highly local. In rainy places, panels may need little attention for years. In dry, dusty, smoky, or pollen-heavy environments, cleaning can recover much more. Bird droppings and partial shade came up again and again as the worst offenders because they can hurt output far more than a thin layer of dust. Second, several technically minded commenters said the post likely overstates the cleaning effect if measurements were taken right after washing. Wet panels run cooler, and cooler panels produce more power. Some of the apparent gain may have been temporary evaporative cooling rather than restored optical performance. That pushed the conversation toward a practical conclusion. Cleaning only makes economic sense when access is easy, dirt is real, and extra output actually matters. Ground-mounted and off-grid systems got the strongest case for cleaning because the labor is low and small efficiency gains can reduce generator use or keep batteries healthier. Roof-mounted systems looked much less attractive once ladder risk, labor, and the chance of damaging panels or yourself were factored in. A separate thread widened into solar economics more broadly. People with old feed-in tariffs and net metering plans said legacy incentives can perversely discourage upgrades or capacity changes, because touching a system can forfeit a much better payout scheme. Others noted that falling panel prices have also changed optimization math. For many installations it is now cheaper to add more fixed panels than to fuss over trackers, perfect angles, or other clever hardware.

Treat panel cleaning as a site-specific maintenance task, not a universal best practice. Check your own production data, inspect for pollen, bird droppings, or shade, and be especially wary of paying for routine cleaning unless your conditions are unusually dirty or every extra kilowatt-hour matters.