A common question among UK solar owners is whether a bit of dirt really matters. In fact, debris on panels does reduce their power output. Any film of dust, pollen, or bird droppings blocks sunlight from reaching the cells. Studies show this can be significant: for example, the National Renewable Energy Laboratory found annual energy losses from soiling up to about 7% in some U.S. regions, and much higher in drier climatesnrel.gov. Even in the UK’s wetter climate, accumulated grime can still knock off several percent of production over time.
- Myth: Rain always cleans them. In practice, rainfall often leaves streaks and mineral spots. Roof panels angled well may self-rinse, but panels mounted flat or on the ground can stay partially dirty after rain.
- Myth: Small dirt deposits have no effect. Even a few percent loss is wasteful over a 25-year lifespan. For example, bird droppings create opaque spots that “obstruct sunlight, reducing the amount of energy absorbed by the solar cells”squeegeesquad.com.
Image: Side-by-side of two solar panels: one dusty and one cleaned. Alt text: “Comparison of a dirty solar panel and a clean solar panel showing visible difference.”
Cleaning regularly ensures panels operate near their rated capacity. The Energy Saving Trust emphasizes cleaning every 12–18 months to keep systems “performing well”energysavingtrust.org.uk. Likewise, UKSPCA-certified cleaners can verify and restore maximum output. In short: dirt really does cost you money. By booking a cleaning, homeowners often recover lost generation and protect their investment.
For guidance on upkeep, see our article on Solar Panel Cleaning vs Maintenance. If you notice a drop in generation, it could be time to Find a Certified Cleaner for an inspection and wash.
Image: A clear sky with two identical solar panels: one is noticeably cleaner. Alt text: “Two solar panels, one clean and one partially covered with dust, highlighting output difference.”
Call to Action: Want peak efficiency? Schedule a professional cleaning to clear away grime. Visit UKSPCA’s Find a Cleaner tool today and keep your panels in top shape.
