So you’ve made the switch to solar—great move. Lower bills, cleaner energy, less reliance on the grid. But here’s something a lot of solar owners don’t realize: if you’re not keeping your panels clean, you’re probably leaving energy (and money) on the table.
Solar panels work by soaking in sunlight and converting it to power. Simple enough. But over time, a layer of dust, bird droppings, pollen, and who knows what else can build up on the surface and block that sunlight from getting through. It doesn’t seem like a big deal, but it adds up.
Depending on where you live and what’s floating around in your environment, dirty panels can lose anywhere from 5% to 25% of their energy output. In some cases, that’s the difference between a normal bill and one that has you scratching your head.
In dry areas—like here in Arizona—it’s especially common for dust to settle on panels and stay there. There’s not much rain to rinse things off naturally. One study out of California found that panels that hadn’t been cleaned for several months saw energy output jump by over 30% after a simple wash.
Think about that: a 30% boost in power just from getting rid of the dirt. No upgrades, no new tech—just maintenance.
There’s no one-size-fits-all answer, but here’s a general idea:
If you’re in a dusty area: every 3–4 months
If you're in a city or suburb with occasional grime: every 6–12 months
If you’ve got trees or birds nearby: keep an eye out and clean as needed
If your energy production dips and there’s no system alert or hardware issue, dirty panels could be the culprit.
If your panels are easy to reach and you’re comfortable doing it, a soft brush, a hose, and a little soapy water will do the trick. Just avoid anything abrasive or high-pressure that could scratch the glass.
But let’s be real, most rooftop systems aren’t that easy to access. In that case, hiring a pro is the smarter (and safer) option. They’ll do a better job, and you won’t have to risk life and limb climbing up a ladder with a sponge.
Cleaning your solar panels doesn’t take much, but the payoff can be big. It’s one of the easiest ways to keep your system running at full capacity and get the most out of your investment.
If you haven’t thought about it in a while, now’s a good time to take a look. Better yet, schedule a professional cleaning. Your system will thank you.