Solar Panel Cleaning: Why, When and How to Do It

Solar power has seen some impressive growth over the past few years. As these technologies have become more affordable and efficient, they’ve become more popular, and that’s great news for the environment. However, the importance of solar panel cleaning often goes overlooked.

Installing solar panels is an excellent way to help the environment and reduce your energy spending. If you want to reach those goals as best you can, though, you’ll need to keep your panels clean.

Why Is Solar Panel Cleaning Important?

Like anything else outside, your solar panels will collect dust and debris over time. That buildup blocks sunlight from reaching the photovoltaic cells, limiting the amount of electricity they generate. Consequently, solar panels’ efficiency can drop by as much as 60% from dust accumulation alone.

With less power coming from your solar panels, you’ll need to buy more from the grid. Using more grid-sourced energy increases your reliance on fossil fuels, leading to a larger carbon footprint.

Long-term energy savings, one of the biggest cost advantages of solar power, will also decline. Less efficient panels mean getting a return on your investment will take longer, making solar less economically viable. By contrast, regular solar panel cleaning prevents this efficiency loss, saving you money and improving your sustainability as a result.

How Often Should You Clean Solar Panels?

Thankfully, it takes time for solar panels to get dirty enough to cause issues. Consequently, you can wait a fairly long time in between cleaning sessions, with most companies recommending you wash them every six months to a year.

Keep in mind that depending on where you live and what’s around your house, you may need more frequent cleaning. If you live in a drier region, you should clean your panels a few times annually, as you’ll have less rainfall to wash dust away naturally. Similarly, if you live near a busy highway airport or industrial area, you may encounter more pollution, requring more frequent washing.

If you’re ever in doubt, you can monitor how much energy your panels generate. If they start to produce less power even when it’s sunny out, it may be time to clean them.

How to Clean Solar Panels

The manufacturer you bought your panels from may offer solar panel cleaning services. You may also be able to find contractors in your area who can clean them. If not, or if you’d rather do it yourself, here’s a step-by-step guide to how to clean solar panels.

Get Appropriate Safety Equipment

Most solar installations are on rooftops, so safety is paramount. Falls are the leading cause of death among construciton workers, with falls from roofs accounting for many of these incidents. In light of that risk, you should make sure you have all the safety equipment you need before going up to clean your panels.

Use a steady ladder, ideally with someone else to support it. You should also wear a helmet and a safety harness if you have to climb up onto the roof. Be sure to work on a clear, dry day to minimize slipping hazards.

Solar panels may also present shock hazards, so wear rubber gloves and turn your panels off before cleaning them. Read through your manufacturer’s care instructions for any additional safety or cleaning tips.

Clear Loose Debris

Once you’re safely on the roof and have shut the panels off, you can start to clean them. To do that, start by clearing any loose debris like leaves from the surface. This will prevent smearing and reduce the risk of scratching later in the cleaning process.

Take a soft brush, ideally on an extendable pole so you can use it from a safe distance, and gently wipe off the debris. A leafblower would work well, too. Whatever you use, be sure it’s non-abrasive. Anything too hard or rough could scratch your solar panels, causing bigger problems than dust accumulation.

Spray Panels Gently With Water

Next, you can use water to spray any remaining dust and debris off of the panels. Like every other step in solar panel cleaning, it’s important to be gentle here. Avoid using pressure washers or high-pressure hoses, as these could damage the panels instead of cleaning them.

Similarly, be sure your water is clean. Many public water systems contain potentially dangerous contaminants like metals or pharmaceuticals. These could leave behind smears as the water dries, reducing your panels’ efficiency, so you may want to filter your water before cleaning with it.

If you’re working on a hot day, avoid using cold water, too, as the dramatic temperature shift could cause the glass to crack. Instead, use warm water and try to clean on a relatively cool day.

Wipe With a Soft Brush or Cloth

If there’s still residue left on the solar panels after rinsing them, you may need to wipe them. Start by using more water and a soft brush, sponge or cloth like you’d use for cleaning your car’s windshield. Gently wipe the surface, being careful not to apply too much pressure to avoid smearing.

If the stains are particularly persistent, you may need a cleaning solution, too. Many cleaning products are too abrasive for solar panels or may leave a residue that blocks sunlight, so you should choose these carefully. Try mixing a mild detergent in water, slowly adding more cleaner if you need more cleaning power.

Dry and Monitor Performance

The last step in solar panel cleaning is to dry the glass and review your work. Use a squeegee or soft, clean cloth to wipe away excess water and detergent. Leaving water to sit on the panels could cause more grime to build up, counteracting the hard work you just put in.

Once your solar panels are clean and dry, keep checking how much power they generate. If it goes up, you’ve done a good job and can follow the same process in the future. If their performance drops, there may be some residue from the cleaning process blocking sunlight. In that case, you should try cleaning them again or contacting a service to handle it for you.

Solar Panel Cleaning Is a Crucial but Often-Overlooked Step

Regular solar panel cleaning will keep your energy bills and carbon footprint low. While it’s easy to overlook this step, it’s an important part of ongoing care and sustainability. Businesses and consumers alike should understand the need for cleaning and how to do it to get the most out of their solar installations.