Is It Time?
Do your panels actually need cleaning?
Many don’t, at least not every year. Your installer probably told you solar needs very little maintenance, and for a lot of systems that’s true. Panel manufacturers like Qcells agree rain usually washes dirt away, but panels shaded by dirt or bird droppings need cleaning. Here’s how to tell if yours is one of the exceptions.
Step 1
Look.
Stand where you can see your panels, or zoom in with your phone.
Clean and reflective
You likely don't need cleaning.
White or dark spots
Usually bird droppings. These block light where they land and often don't rinse off.
A dull, hazy, or yellow-green film
Usually pollen or dust. Common after spring and harvest.
Leaves, needles, or dirt packed along the bottom edge
Water can't drain, so grime keeps building.
Step 2
Check your monitoring app.
Compare this month to the same month last year.
Close to last year
Dirt isn't a meaningful problem right now.
Gradually lower over months, with visible grime
Cleaning will likely help.
Suddenly much lower, or one section at zero
That's usually equipment, not dirt. Call your installer first. They can check inverters, optimizers, and wiring remotely.
Sudden production drop? Call your installer first. Dirt builds slowly — a sudden drop is almost always an equipment issue.
Step 3
Consider your site.
Cleaning tends to pay off faster if you’re:
- Within a mile or two of crop fields, dairies, or gravel roads
- Under or near large trees
- A favorite spot for birds
- On a low-tilt or flat roof
- 2+ years without a cleaning
When I clean in Southern Wisconsin
Late May to June
After spring pollen, before peak production months.
Fall, before freezing weather
After much of the harvest dust and summer bird activity. I don't wash panels when frost is possible, per manufacturer instructions.
Anytime
Heavy bird droppings or visible buildup.
Still unsure?
Text me a photo of your panels at (608) 571-4173. I’ll tell you honestly if they need cleaning or if you can wait another year.
(608) 571-4173
On an annual or bi-annual plan? This timing is already handled — you’re booked before pollen season. See the plans