If you’ve spent any amount of time traveling across the country, you’ve probably noticed a pattern: the longer you’re on the road, the less attention your RV roof gets. When most of us first buy a rig, we give it the royal treatment—fresh wash, shiny finish, everything spotless before that first trip. But as the miles add up, the roof becomes one of those “out of sight, out of mind” areas.
And that’s exactly why so many RV owners start to wonder why their solar panels aren’t producing the way they used to.
Before you assume something expensive has failed or that your system needs a full rebuild, it’s worth taking a look at one of the simplest—and most ignored—causes of solar loss: a grimy, neglected solar panel.
Welcome to another Tech Tip Tuesday from the National RV Training Academy, the largest hands-on RV training school in the country. Today’s tip focuses on a maintenance task that doesn’t get talked about nearly enough.
Why Dirty Solar Panels Matter More Than You Think
Solar panels seem pretty straightforward. They sit up there on the roof, soaking in the sun, silently doing their thing. Most of us don’t give them a second thought after installation—until the numbers start slipping.
The truth is that a layer of dust, pollen, road grime, diesel soot, ash, or anything else you’ve passed under in your travels can dramatically reduce the panel’s ability to capture sunlight. You don’t even need a thick layer; even a thin haze will affect output.
If you could compare a freshly cleaned panel side by side with one that’s been exposed to the elements for a few months, the difference is almost laughable. One looks ready for a showroom floor. The other looks like it’s been through every state fair and dust storm in the country.
Fortunately, the fix is simple—and you don’t need anything complicated or expensive.
What Not to Use on Solar Panels
One of the biggest mistakes people make is reaching for standard glass cleaner. It feels logical—after all, they look like glass, and it works great on your windows.
But a lot of glass cleaners contain ammonia or additives that can damage the protective coatings on your solar panels. Over time, those chemicals can etch, cloud, or weaken the surface.
So while it might seem handy, skip the window cleaners.
What Works Best for Cleaning RV Solar Panels
You only need two things:
- Regular dish soap (Dawn is a popular choice)
- Clean water
Mix a small amount of dish soap with water in a bucket. That’s it. No fancy formulas or expensive “solar-safe” cleaners required.
Once the panels are clean and dry, there’s an optional step many RV owners swear by:
A thin coat of Rain-X.
It helps keep dust and dirt from sticking as quickly, and it makes the next cleaning easier. Just a light layer is all you need.
Tools That Make the Job Easier
You don’t need a specialized kit. In fact, you can pick up everything you need from a local Dollar Tree or hardware store.
Here are the best options:
1. Microfiber Cloths
These are cheap, soft, and effective. Get a small pack of them, dip one into your soapy water mix, wring it out well, and wipe the panel in smooth, straight lines. Working like a “typewriter” across the panel helps ensure you don’t miss spots.
2. Wash Mitts
If you’re the type who enjoys washing cars, you probably already own one. They slip on your hand and make it easy to scrub without applying too much pressure.
3. Shop Towels (for emergencies only)
They work, but they’re not ideal for repeated use. Save these for times when you’re in a pinch.
Why Most RV Owners Forget About This Step
The biggest reason? Your solar panels are on the roof.
You’re not looking at them every day. Unlike the side of your RV, where dirt buildup is obvious, the roof collects grime quietly. Days turn into weeks, and before you know it, your solar output has dropped and you’re troubleshooting problems that don’t exist.
Dirty panels won’t ruin your system—but they will drastically reduce performance.
If your solar setup isn’t producing like it used to, a simple cleaning might be all it needs.
A Quick Note About Solar Output Issues
A dirty panel is only one potential cause of reduced production. Wiring issues, shading, failing equipment, or improper settings can also affect solar performance. But cleaning your panels is the easiest place to start—and it’s the one most people overlook entirely.
Want to Learn RV Systems Inside and Out?
If you enjoy learning how things work on your RV and want to turn that knowledge into a career—or simply become the most capable RVer on the road—the National RV Training Academy can help you get started.
Talk to a student advisor today and learn how you can earn certifications, start your own business, and help fellow travelers keep their rigs running smoothly.