Guide
How Much Do Dirty Solar Panels Cost You?
Dirty solar panels cost you the electricity they don’t make. Losses depend on how dirty the panels are: light dust may only shave off a few percent, while heavy dust, pollen and bird droppings after a long dry season can cost much more. Your own monitoring app is the best way to see the real number.
By Braylon Howard, owner of High Tide Window Cleaning · Updated October 2026
Why do dirty panels make less power?
Solar cells make electricity from the light that reaches them. Dust, pollen, salt film and bird droppings block part of that light. A single dropping matters more than it looks, because shading part of one cell can pull down the output of the whole panel.
How can you measure what dirt is costing you?
Open your solar monitoring app and compare production on clear, sunny days. Look at this month against the same month last year, or check output the week before and the week after a cleaning. If production on clear days has slipped and nothing else has changed, dirty panels are the likely cause.
What does a few percent mean in dollars?
Here’s a worked example using round numbers. A home system that makes 600 kWh a month, at a utility rate of $0.40 per kWh, produces about $240 of electricity a month. If dirt cuts output by 5 percent, that’s 30 kWh, or about $12 a month. At 10 percent, it’s about $24 a month. Plug in your own system size and rate.
System output (example)
600 kWh / month
Value at $0.40 / kWh
About $240 / month
5% soiling loss
About $12 / month
10% soiling loss
About $24 / month
When does cleaning pay for itself?
Solar panel cleaning from High Tide Window Cleaning costs $12 per panel, so a 20-panel system costs $240. Whether that pays back depends on how dirty the panels get and your utility rate. Dusty rural sites and arrays that haven’t been cleaned in a year or more usually see the biggest jump, and a clean panel also lets you spot real problems in your monitoring data.
Key takeaways
- Loss depends on how dirty the panels are
- Dry Central Coast summers make it worse
- Use your monitoring app to measure it
- Compare the lost value with the cleaning cost
Need it done?
$12 per panel, soft brushes and deionized water.
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