"Don't solar panels need a lot of maintenance?"
SunPower gets this question 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.
Since SunPower's panels are the most efficient on the market1, 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, or if you have been impacted by smoke and ash from wildfires in California or Oregon, you may need to clean your panels. Some homeowners are able to do this themselves. Others may choose to have them professionally cleaned.
For example, in Bakersfield, Calif., where SunPower by Sun Solar installs solar systems, it doesn't rain much between spring and the wintertime, making regular cleanings a good idea, according to Ryan Olson, manager of Sun Solar'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.
If the panels are hard to access, such those on a two-story home, Olson suggests buying a high-pressure hose nozzle. These can be found at any home maintenance store. Find a safe place to stand and 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.
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.
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 can damage your panels, resulting in voiding your warranty.
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
A larger multi-story home such as this one (above) would require a professional solar panel cleaning service.
Contact your SunPower dealer to ask about their cleaning service. Many window washing companies also offer solar panel cleaning now.
Some other tips:
Do a monthly visual inspection to look for any dust buildup.
If you live in the western United States where wildfires are annual occurrences, be sure to check your solar panels for ash or soot build up after nearby fires have been safely contained.
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.
- 1. Based on datasheet review of websites of top 20 manufacturers per IHS, as of June 2020.