How much are dirty panels costing you?
Two questions, instant answer — built from local soiling data for 85 US metros.
Not sure? Your installer paperwork lists system size in kW — or count panels and pick the closest.
How the estimate works
We multiply your system size by a typical production factor and electricity rate for your state, then apply a soiling-loss percentage derived from your metro's position on our national Grime Index. Losses of 5–25% from soiling are documented by NREL research in dusty regions; our per-metro figures stay conservative inside that range.
No — it's an honest estimate. Real losses depend on your roof tilt, nearby trees and fields, rain patterns in a given year, and how long since the last clean. The estimate uses typical values so you can judge whether professional cleaning pays for itself.
Yes. Soiling loss is reversible — most homeowners see a measurable production bump the same day panels are cleaned. Frequency matters more than perfection: in high-dust metros, 2–4 cleanings per year keeps losses near zero.
Assumptions: state-typical solar production factors and average residential electricity rates; soiling-loss percentages derived from our per-metro Grime Index within NREL’s documented 5–25% range for high-dust regions — see the dirtiest cities in America ranking for how your metro compares. Estimates are informational, not a production guarantee. Ready to fix it? Get free quotes from local pros.