How Much Does Washing Solar Panels Help?

I’ve been looking for every advantage I can get when it comes to solar charging these days. With the days so short and the sun so low in the sky when it is up, every little bit helps. I hadn’t washed my solar panels in a while, so I decided to check how much power I was generating before and after washing them to see just how much of a difference it made.

As you can see in the top picture, they were pretty dirty. I’ve been in the desert for over a month. Yesterday the wind kicked up so much dust I couldn’t see the surrounding mountains. Certainly, a quick Windex and wipe would improve how much power my panels generated, right?

I took this measurement immediately before washing my panels. This was at roughly 2:30 pm local time. This is just about the most charging my 600 watts of rooftop solar gives me during the day because the sun is so low in the sky these days.

I took this measurement immediately after washing the panels. There were no clouds in the sky. As I watched the Renogy app in real-time, I could see the power output fluctuating between 225 and 230 watts, both before and after washing my panels. In other words, it didn’t change a darn thing.

So if you can’t reach your rooftop solar panels, don’t worry about it. Cleaning them doesn’t seem to make a difference when it comes to power generation. If you’re just lazy about it, that’s fine too. I usually am. Based on the results of this test, I will continue to be lazy when it comes to keeping my solar panels clean because it doesn’t seem to make any real difference anyway.

I’m not done experimenting, though. Stay tuned for more testing to see if anything else makes a difference.