After asking how to read their electric bill, the second question that most new solar homeowners ask California solar installer Barry Cinnamon is “how often should I clean my solar panels?”
Cinnamon, who does a weekly podcast called the Energy Show, says that it depends. You only need to clean solar panels if they get dirty enough to reduce your solar panels’ production enough to cost you real money.
And that depends on the rainfall in your area, but also on the cost of electricity and the size of your solar system. For example:
- The occasional heavy rain will clean most solar panels well enough to keep them producing near full capacity; unlike groundwater, which contains minerals that can gunk up the surface of PV panels, rainwater gives panels a nice clean
- In dry areas that have long periods between heavy rain like California or the Southwest panels can get dirty enough to require cleaning
- If you have high electricity prices, every bit of solar power you lose to dirty panels is more valuable, so it makes more economic sense to clean them more frequently
- Larger solar systems, above 10 or 15 kilowatts, give more financial benefit from cleaning
In Virginia, most homeowners with an average size solar array of 5 kilowatts can count on the occasional heavy rainstorm to clean their solar panels enough to keep them producing at a high level. And since electricity prices here for homes are about 10 or 11 cents a kilowatt hour, in most cases, it’s not worth spending $200 or more a year in Virginia to hire a solar installer to come by and clean your panels.
Getting Help Can Make a Big Difference
Should you clean solar panels yourself, then?
The quick answer I give our customers is “No.” Berry Cinnamon agrees, and he cites two main reasons why you shouldn’t clean your own solar panels.
- Safety. Unless you have a ground-mount system, which is the exception, your solar panels will be installed on the roof of your house. Climbing up there is dangerous — you can fall and risk seriously injuring yourself. But it’s also dangerous to deal with the wires and other electrical equipment that make up a solar system. Unless you turn off your system properly beforehand, you may expose yourself to risk of serious electric shock navigating the live wires that connect your solar panels. And if you’ve got a bucket of water in your hand? I don’t even want to think about it.
- Damage to Components. It’s easy to scratch or even crack the glass surface of your solar panels with the wrong cleaning materials or technique. And spraying solar panels with your garden hose may be one of the worst things you can do. If you have hard water, the minerals from your water can condense on the surface of the solar panels as they dry, creating a white film that’s almost impossible to get off but can reduce your energy production by 20% or more. Professionals use a detergent that deactivates any minerals found in the water they use. And of course you may void your warranty if you try to clean your own panels.
So, if you’re going to get your solar panels cleaned, get a professional solar installation company to do it. They’ll come by in a truck with two people, they’ll use a secured ladder and may even tie in to your roof with harnesses to stay safe, and they’ll use tools and detergents that are safe for PV panels.
When Solar Panel Cleaning in Virginia is Worth the Cost
A solar installer may charge you $200 or $250 for a visit, so it’s only worthwhile if your cleaning your panels will save you more than that. In most places in Virginia, for the average size home solar system, you don’t need to spend this kind of money. Big rain will keep your panels clean enough.
However, if you’re in a dry part of the state or even in a farming area where your panels get especially dusty, it may be worthwhile to have your panels cleaned once or twice a year.
Otherwise, in Virginia, you probably only need to get a solar installer out once every five years for a cleaning. You can combine the visit with an inspection, just to make sure all the wires are still connected properly and that there aren’t any squirrels nesting in your racking.
Main Street Solar or any experienced Virginia solar installer can clean and inspect your home solar system as needed. More importantly, when you first have your solar panels installed, your installer should be able to advise you on any cleaning or other maintenance required.
Most of the time, solar panel maintenance is as close to zero as anything on your home. But for peace of mind, it’s good to know that everything’s working correctly and that you’re generating as much solar power as you can. That’s why Main Street Solar offers energy monitoring software with every installation that helps us keep tabs on your system and alerts us to any potential issues so that we can respond if necessary.
Meanwhile, if you’d like to know more about solar panel cleaning, you can listen to Barry Cinnamon’s whole podcast about it using the player below:
— Andrew Brenner, Main Street Solar