What water should you clean solar panels with? Not the hose.

Angel Oquendo Owner, Sunshine Solar Panel Cleaning · Waianae

Rain alone won't clean your panels, just as rain alone won't clean your car. And a garden hose won't either, for the same reason: what's in the water stays on the glass when the water dries. You've seen the spots on a car that air-dried after a rinse. That's the minerals. On a solar panel they shade the cells the same way dirt does.

What runs through the truck

The setup in the truck is a water filtration system. We plug your water in and it runs from a sediment carbon filter into an RO filter into a DI filter, and it comes out pure water. Pure water dries and leaves nothing behind. No residue spots, no film.

• Sediment and carbon filter. Takes out the grit and the chlorine.
• Reverse osmosis. Takes out most of the dissolved minerals.
• Deionisation. Takes out what's left. What comes out is as close to pure water as you can get on a driveway.

When the truck can't get close

Sometimes we can't get the truck near enough to the house to run everything. For those jobs we have filter sticks we call dry water. It's a technology I don't know too much about; all I know is it works really well, and it's expensive. If we can't run the truck, we run the dry-water stick, and it works fantastic.

Why the brush has to be water-fed

All of our brushes are rotating brushes. They spin, and water pours out of them the whole time, so the brush is cleaning and rinsing in the same pass, forwards and backwards over the whole panel. Some panels need a little extra rinse when they're covered top to bottom, and we'll show you a video of that.

A lot of window-cleaning guys use window-cleaning brushes to clean solar panels, and it just does not work. It's like a dirty mop on your floors: you're just pushing dirt around. Then you have to have a hose up there to rinse, and now the minerals are back on the glass.

"If you pull up to somebody's house with a brush from Home Depot and use their water hose, and then ask for a ladder, there's a problem. Cheap is cheap."

Where the gear comes from

Most of our solar panel equipment comes from Germany. Their stuff lasts so much longer. The Europeans were the ones who really started putting solar on houses, before anybody in America did, because their energy was so expensive. Everything is imported there. Just like Hawaii.

Related

• How we clean
• What a visit includes