Do solar panels need cleaning?
This question arises from homeowners regularly, and it’s understandable given that no one wants to worry about climbing up on a roof to care for their solar panels.
Solar panels work by converting sunlight into electricity, so the cleaner your panels are, the more efficiently they’ll be able to generate clean energy for your home or business.
Since SunPower’s panels are the most efficient on the market they’ll make more energy than competing panels in a variety of low-light situations, but any panels covered with too much dirt or debris will produce less power.
In most cases, the loss of power isn’t significant — maybe 1 to 4.7 percent. But one study found that long-term dirt buildup can reduce a solar panel’s electricity production by as much as 20 percent.
HOW TO CLEAN YOUR SOLAR PANELS
The good news is that seasonal rain and snowmelt usually washes off any dirt or animal droppings that may have accumulated. But if your area receives very little precipitation and has dusty, windy weather, you may need to occasionally clean your panels. Some homeowners are able to do this themselves or they may choose to have them professionally cleaned.
For example, in Bakersfield, Calif., where SunPower by Precis installs solar systems, it doesn’t rain much between spring and the wintertime, making regular monthly or bimonthly cleanings a good idea, says Ryan Olson, manager of Precis’s service department. Because the Central Valley is an agricultural region, a lot of dust gets stirred up around harvest time in August and September.
“They’re shaking a lot of the almond trees around here and that (debris) hurts (electricity) production,” Olson said.
Fortunately, cleaning solar panels is easy for ground-mounted systems, or for rooftop solar systems on a typical one-story house. Olson recommends homeowners use a soft-bristle brush with an extended handle, like the type used to clean off an RV. And don’t forget to choose an environmentally friendly soap.
If the panels are hard to access, such those on a two-story home, Olson suggests buying a high-pressure hose nozzle with an attachment that holds soap. These can be found at any home maintenance store. Find a safe place to stand, spray soapy water on the panels and then quickly rinse them off.
“It really is that simple,” Olson said.
Do-it-yourselfers should keep some other things in mind:
- As a rule, stay on the ground. Never get up on your roof without a secure ladder and proper fall-protection equipment.
- Turn off your system before start you cleaning. Consult your SunPower® solar manual to see how you turn off your system to protect it. If you’re unsure, ask your SunPower dealer for help.
- As a rule, avoid using hard, or mineral rich, water. It can damage panels over time. If your area only has hard tap water, you can buy an inexpensive water-softening hose attachment to filter out minerals. Otherwise, you can use distilled or de-ionized water.
- Use soft brushes and squeegees. Don’t use abrasive brushes, pads or powders.
- Clean early in the morning or in the evening when the panels are cool. During the heat of the day, water and soap can evaporate quickly, which risks smearing the soap and dirt.
- When using a high-pressure water nozzle, don’t get close to the panels. While they’re extremely durable, you don’t want to damage them.
HIRING A PROFESSIONAL SOLAR PANEL CLEANER
In many cities there are businesses that specialize in solar panel cleaning, but it’s also a service that many window washing companies now offer.
Cactus Desert Window Cleaning Co-Owner Aymee Angeles Wilburn says many homeowners have their solar panels professionally cleaned quarterly or even just once or twice a year.
She said the cleaning fee that she charges is typically about $2 to $4 per panel, depending on how accessible the panels are and how dirty they are. A typical job takes 15 to 30 minutes.
“They’re easy,” she said. “There isn’t a lot of detail (to clean) like there are with windows.”
Some other tips:
- Do a monthly visual inspection to look for any dust buildup. Also, you can watch your bill for any noticeable drop in efficiency. Only then should you worry about cleaning. Even then, in most cases, nature is going to clean them for you.
- Don’t expose yourself to any risk. If you have any doubts about your ability to safely clean your panels, hire a professional.
Now that you can see that having solar panels is not a high-maintenance commitment, visit our solar calculator to see how much you might save going solar.