Should You Clean Your Solar Panels?

Solar panels not only have a low impact on the environment but also on your everyday life. In many circumstances, you can install them and not worry about further maintenance, such as cleanings. There are some cases, however, in which it is a good idea to clean them—and in those cases, it's crucial to clean them properly.

When Cleaning Is Necessary

Anything that makes your panels less efficient is slowing down the return on your investment. Here are some situations where that might be the case:

• Your panels are near a busy roadside, airport, or industrial facility. Particulate matter (such as road dust or diesel soot) can accumulate on your panels. Since the panels are dark, you may not even notice the build-up.
• There are nearby trees. Your panels should be located so that trees don't obstruct sunlight, but it's worth inspecting your panels in autumn to check for leaves that may have accumulated on your panels.
• Your panels are not tilted, such as on the flat roof of a solar carport. A 2018 study found that horizontal solar panels were up to 14% less efficient than tilted solar panels due to dust accumulation.
• You have bird feeders nearby. Solar panels can make an ideal perch for birds, and bird droppings will need some extra effort to remove.
• You live in an especially smoggy city, windy desert, or along the ocean. Salt, sand, or smog may accumulate on your panels and impact efficiency.
  

When Cleaning Is Not Necessary

Unless you are in a situation that necessitates manual cleaning, you can let nature do the solar panel cleaning for you. If you live in an area where it rains or snows regularly, the rain or snowmelt will act as a natural cleaning solution.

There are a couple of other reasons you probably don't need to regularly clean your solar panels:

• You don't own the panels. If you are a member of a community solar farm on a monthly (or annual) subscription plan, the owner of the panels is responsible for cleaning them. Check your subscription plan to see if periodic cleaning is included. If it's not, ask before you sign.
• Snow will melt. There's little reason to remove snow from panels. Some sunlight will penetrate even thick snow, and the heat generated by the panels as they produce electricity will melt the snow relatively quickly. The tilt of most panels is steep enough that the snow will just slide off (and do the washing for you).
  

How to Clean Your Solar Panels

It's still a good idea to conduct a periodic visual inspection of your panels to see if they need cleaning. Check first with the manufacturer or installer of your solar panels for any specific recommendations on cleaning your panels. For example, bifacial solar panels may need cleaning on both sides.

If you do clean your panels, here are some things to keep in mind:

• Use water only, unless you have hard-to-remove debris on your panels, such as bird droppings.
  
• Use a simple garden hose. A high-pressure sprayer could damage your panels.
• For more stubborn substances, use plain dish soap and warm water with a soft cloth or sponge, then rinse with plain water. Scraping or brushing your panels has the possibility of doing more harm than good.
• Unless your panels are not pitched properly, let the water run off by itself. Avoid using a squeegee, which might accidentally scratch your panels. Streaks left by cleaning will disappear in the next rain or snow.
• Avoid cleaning your panels during the middle of a sunny day, as the panels can get very hot. Hot panels can quickly dry soapy water and leave a residue on your panels.
  

Should You Invest in a Solar Panel Cleaning Service?

Again, the answer is probably not. If cleaning is advised, it will be less expensive to do it yourself rather than hire a solar panel cleaning service.

On the other hand, if your garden hose isn't powerful enough to reach your rooftop panels from the ground and you don't want to climb onto the roof, hire a professional to do it for you. Make sure to ask about their cleaning methods before hiring someone.

If you can easily clean your panels without damaging them, then doing so could make your panels more efficient and your investment more profitable. But depending on where you live and other environmental conditions, it may just be easier and cheaper to let nature do the job for you.