How often should you clean solar panels in Hawaii?

Angel Oquendo Owner, Sunshine Solar Panel Cleaning · Waianae

The short answer for most houses on Oahu is once a year. Here's how we think about it.

The first clean is the big one

If your panels have never been cleaned since the installer left, the first clean is where we get all of that build-up off: years of black mold, red dirt, or both, thickest along the top or bottom edge. That's the visit where people see the biggest jump in production, and it's the one we price as a first clean.

After that it's maintenance

Once we clean your panels once, the price goes down. Every year you clean your panels with us, your rate drops, because now we're doing maintenance: keeping the dirt off before it bakes on, instead of removing what's been baking for five years. That's the whole idea. Keep them clean, keep the return on your investment where it should be.

What changes the answer

• Near the water. Waianae, Ewa Beach, Hawaii Kai, the North Shore. Salt haze comes back faster.
• Under trees or near open land. Leaves, pollen, and red dirt off the plateau in Mililani and Wahiawa.
• The wet side. Kaneohe and the valleys grow black mold, and mold doesn't rinse off in the rain.
• Pigeons. If birds are under the array, cleaning alone isn't the fix. That's an assessment and bird proofing.
• Painting. A customer pointed out in a review that a house repaint puts overspray on the panels. Clean after the painters leave.

We'll tell you after we see your roof. Some houses are fine yearly; a few need more; nobody needs less.

The signs it's time

Your monitoring app showing less than the same month last year. A bill that's crept up. Streaks you can see from the driveway. One of our customers wrote that since the first year we cleaned his panels, his electric bill has stayed at the minimum charge except for one month of near-daily rain. Another said his output went from about 2 kW to over 8 kW after a clean. Those are their numbers, in their reviews; every roof is different. But dirty panels don't fix themselves.

"Rain alone won't clean your panels, just as rain alone won't clean your car."

Related

• Do dirty panels reduce output?
• What it costs