If ash has landed on your solar panels, wait. Let the ash stop falling and let the air clear, then have the panels cleaned by hand before the next rain. Don’t blast the ash off with a hose or pressure washer. Dry ash is gritty, and rain can turn it into a paste that’s harder to remove than the dust it landed on.
Here’s what ash does, what to do and not do, and how we handle it.
What does ash do to solar panels and windows?
Wildfire smoke leaves two things behind. One is coarse ash, the flakes and grit you can see on cars and patios. The other is a fine film of smoke residue that settles on glass as a hazy, sometimes greasy coat. Both land on panels, windows, skylights, patio covers and anything else outdoors.
On panels, the layer blocks some light from reaching the cells. It also sits there. Southern California is dry for most of the year, so ash from a fall fire can stay on the glass until the first heavy rain, and as we describe below, rain doesn’t always help. Homes near the hills are hit most. Chatsworth, Porter Ranch and Sylmar back up to open land, and hillside areas such as Topanga Canyon and Malibu sit even closer to fire country. But ash travels on the wind, and homes far from the flames can get it too.
Why not just blast it with a hose?
It’s tempting. It’s also a bad move for a few reasons.
- Dry ash is abrasive. Pushing it around on glass can leave fine scratches.
- A hose spreads the ash into a smear that dries into a film.
- A pressure washer can force water into places it shouldn’t go. We never use high pressure on panels or glass.
- Standing on a roof covered in ash and dust is a slip risk. Homeowners shouldn’t climb up there.
If you must do something before a professional visit, leave the panels alone and keep your windows closed.
When should panels be cleaned after a fire event?
Wait for two things. The first is for ash to stop falling. Cleaning while it’s still coming down just means doing it twice. The second is for air quality to improve. Smoke and ash in the air aren’t good to breathe, and cleaning crews and homeowners shouldn’t be outside working in it.
Once the air is clear, don’t wait too long. Aim to clean before the next rain. In practice, that means:
| Situation | What to do |
|---|---|
| Ash still falling or air quality poor | Wait, stay indoors and keep windows closed |
| Ash has settled, no rain in the forecast | Schedule a cleaning soon |
| Rain in the forecast | Try to clean before it arrives |
| Rain has already fallen on the ash | Expect a paste or film, and plan on more soaking and brushing |
Fire season often overlaps with Santa Ana wind days, and those winds can stir settled ash back into the air. If you’ve had a cleaning and more ash follows, it may need a second visit.
What does rain do to ash?
Rain doesn’t wash ash away the way it washes off a clean surface. Ash mixes with water and can turn into a gray paste. As it dries, a film remains, often in streaks and in a line along the bottom of each panel. The same thing happens on windows, on stucco, and in gutters. That’s why timing matters. For more on how rain and dust combine, see how often to clean solar panels.
What about the air quality?
Take it seriously. When the air is smoky or ash is falling, stay indoors, keep windows and doors closed, and follow local air quality guidance. That goes for homeowners and for us. We won’t work outside in conditions that aren’t safe, and neither should you. Check your local air quality reports and health guidance before you plan any outdoor work.
Don’t forget the roof, gutters and windows
Ash lands everywhere. Panels get the attention, but a few other places are worth thinking about.
- Windows and skylights pick up smoke film that doesn’t rinse off easily. Window cleaning by hand with purified water handles it.
- Gutters fill with ash and burnt debris. Wet ash is heavy, and dry debris in gutters is a concern in fire country. Gutter cleaning clears it.
- Stucco and walkways hold ash too. Our house washing and softwash service handles the exterior, and we pressure wash walkways only.
- Screens collect smoke residue. Screen repair covers damaged ones.
Will insurance cover ash cleaning?
We can’t say. It depends on your policy and your situation, and we’re not able to give legal or insurance advice. Call your insurance company and ask. In the meantime, take photos of the ash on your panels and roof before cleaning, and keep any receipts.
How long does ash stay a problem?
It depends on the weather. With no rain and no wind, it sits where it landed. A breeze moves it around, and a hot, dry Santa Ana day can lift settled ash and drop it again somewhere else. That’s why a second visit is sometimes needed.
After the first real rain, the loose ash is gone, but the film and any paste it left behind are still there. Gutters, window ledges and the lower edge of panels are the usual places to look. A quick check from the ground after the storm tells you whether a cleaning is still needed.
Do windows and skylights need the same care?
Yes. Smoke film clings to glass and doesn’t always rinse off with plain water, and ash on a dry window scratches the same way it does on a panel. We clean windows by hand with soft brushes and purified water, the same method we use on panels, with no high-pressure washing on glass.
Can I do anything myself while I wait?
A few safe things, none of them on the roof.
- Keep windows and doors closed while ash is falling
- Take photos of the panels, roof and windows if you want a record
- Leave the panels and glass alone until the ash has settled
- Check your installer’s or panel manufacturer’s cleaning guidance
- Look at your monitoring app to see how production changed
Please don’t climb onto the roof to check. If you can see the panels from the ground or a window, that’s enough.
What do we do after ash?
We clean the panels by hand with soft brushes and purified water. We don’t pressure wash panels or glass. Ash gets soaked first so it lifts instead of scratching, then brushed and rinsed until the glass dries clean. Heavy ash film can take longer than ordinary dust, and the estimate reflects that. See what changes the price for how we think about it.
Check your installer’s or panel manufacturer’s cleaning guidance as well. After a cleaning, your monitoring app is the best way to see what changed. We explain how to read it in does cleaning solar panels increase output.
Get help after a fire event
If ash has settled on your home and the air has cleared, we’re here. Call (818) 913-1626, Monday through Saturday, 7am to 7pm, read about solar panel cleaning, or see every area we cover. Estimates are free.