Solar Panel Cleaning: A Quick Guide

Prospective homeowners often ask about solar panel cleaning when they're considering purchasing a solar system. They may wonder, "Does cleaning solar panels make a difference in solar system performance?" 

The short answer: Yes. Cleaning your solar panel can reduce your electric bill because it allows the maximum amount of sunlight to penetrate your solar panels.

In this guide, we'll comb through everything you need to know about cleaning solar panels and why this regular maintenance is worth it. Solar panel cleaning can also help you reach the break-even point for your system faster.

Let's explore why solar panels need cleaning, how often they should be cleaned, how to clean them, the cost to clean solar panels, finding a cleaning service and alternatives to cleaning solar panels on the roof (safety first!).

Do Solar Panels Need Cleaning?

While you don’t necessarily have to clean them, dirty solar panels aren’t as efficient at energy production when build-up accumulates. According to U.S. government research, dirty solar panels can produce up to 7% less power. It's easy to imagine the ways in which they might get dirty:

• Bird droppings and dust can prevent light from reaching the solar cells.
• In many cases, rain can get the worst of the build-up off your solar panels. However, rainwater can leave grime that reduces efficiency.
• Smog and particulate matter can diminish solar panel performance, particularly in urban areas with high air pollution levels.
• Leaves can cover your solar panels in autumn or during storms. Checking for leaves during specific times of the year helps maximize energy production.
• Thick pollen can create a haze that prevent light from penetrating your solar panels.
• Sea salt can corrode solar panel components, particularly metal parts. It can also contribute to algae growth and increase salt deposition.

Consider your surroundings – if you live in Arizona, you might have problems with dust and if you live in seaside California, you might have issues with salt spray. Living in the woods in Idaho might give you problems with pine needles.

How Often Should Solar Panels Be Cleaned?

Here's a common question: How often should solar panels be cleaned?

Residential solar systems are built to last – most residential systems are projected to last 25 – 30 years. However, that doesn't mean you can get them installed and assume they'll "clean themselves" for the next two decades. 

In fact, many solar installers recommend that you clean your solar system up to four times per year, to keep your panels working efficiently throughout their expected lifespan. Depending on your location, you may get away with cleaning your solar panels every 6 months. 

However, if you notice dust or other obstructions on your solar panels, you might have to clean them more often than that.

With many solar systems, you can track production using an app, which can indicate whether your solar system is ready for a cleaning.

How Do I Clean My Solar Panels?

Have you asked, "How do I clean my solar panels? And how do I clean solar panels on the roof?!"

Great questions.

You can clean them yourself, but since solar panels are often perched precariously on steep roofs or in hard-to-reach locations, this can be a safety issue. They also generate electricity, which can also pose danger.

In the next section, we'll walk through methods you can use to clean your solar panels and solar panel cleaning equipment.

What Is The Cost To Clean Solar Panels?

When you clean your solar panels, you have two basic options: You can clean the panels yourself or have a cleaning service take care of them. 

If you prefer the DIY route, you might already have the basic tools you need to clean the panels on your own. We'll cover the actual tools you need later on. 

It will typically cost you less than $200 to get your solar panels cleaned professionally. However, the price you'll pay depends on where you live and the cost of living in your area.

Finding A Solar Panel Cleaning Service

Let's take a look at a few tips to select a solar panel cleaning service.

If you haven’t selected your installer yet, ask those on your shortlist if they offer free or discounted cleaning services. If you already have solar panels, find out whether the company that installed your solar panel will clean them. Some companies install solar arrays and offer cleaning services.

You can check with a company that normally cleans windows – they may also clean solar panels. There are also businesses dedicated solely to cleaning rooftop solar panel systems for homes.

What solar panel cleaning services should you use? Research reliable cleaning companies in your area and ask about their processes, rates and experience cleaning solar panels before you make a decision. If you live in a cold climate, you might also ask them about dealing with snow on solar panels.

Going DIY: The Solar Panel Cleaning Equipment You Need

If you plan to clean your own solar panels (many homeowners choose this cost-saving option), here's how to go the DIY route:

• Make sure you have specific cleaning tools, like a non-abrasive sponge or scrub brush and a squeegee to remove excess water. Avoid tools that have an abrasive edge so you don’t scratch your solar panels.
• A regular garden hose can tackle light dust and debris. Avoid high pressure washers because the pressure may damage the cells.
• Removing leaves or snow requires a specialized solar panel rake, but again, avoid any cleaning tools that could scratch the panel surface.
• Stock up on regular dishwashing liquid or specially formulated window soap. You can also mix up a gentle solution using non-abrasive detergent or soap (½ teaspoon) with water (2 cups) and vinegar (¼ cup) for your solar panels. Always avoid harsh cleaning chemicals.

Once you have your tools, rinse your solar panels with clean water from a hose to clear away loose debris. Grab a bucket and fill it with clean water, adding a small amount of soap – it really doesn't take much to fully clean your solar panels.

Next, use a soft scrubber or a sponge to gently wash the surface of the panels and rinse solar panels with clean water to remove all traces of soap. Squeegee the panels dry. Avoid scrubbing or watering the sides or undersides of your panels – you don't want to destroy wiring harnesses or cables. 

Pro tip: Avoid cleaning your panels during the hot, sunny afternoon hours because your soapy water may dry before you can give your panels a final rinse. Stick to cleaning them during the cooler morning or evening.

Alternatives To Cleaning Solar Panels On The Roof

You may be able to avoid getting up on your roof to clean your panels altogether. Some products claim to coat solar panels to reduce the need for cleaning. These products often offer hydrophobic coatings, which allow water to flow off more easily. However, it has been reported that applying an extra coating to clean solar panels may hinder panel efficiency.

You can also purchase sprinkler systems for solar panels to help ensure optimal efficiency and energy production. These products can eliminate the need to climb on your roof and put yourself in a potentially dangerous situation.

The Bottom Line

Do solar panels need to be cleaned regularly? 

Yes! However, it's important to know that you don't have to scrub them every week – they're more low maintenance than that. However, you want to mark dates on your calendar four times per year because regular maintenance can improve efficiency and help you reach your system's break-even point faster.

A few things to look out for: bird droppings, grime from rainwater, smog and particulate matter, leaves, pollen and sea salt for those who live by the ocean. 

You can clean them yourself (being mindful of the safety concerns of walking around on your roof) or hire a company to clean them for you. Cleaning service fees usually depend on the cost of living in your area. Research reliable cleaning companies in your area and ask about their processes, rates and experience before you hire. 

If you choose the DIY route, gather the materials you'll need: a non-abrasive sponge or scrub brush, squeegee, garden hose, bucket, solar panel rake and regular dishwashing liquid. You'll want to avoid harsh cleaning chemicals. Gently wash the surface of the panels and rinse solar panels with clean water. Squeegee the panels dry, avoiding cleaning during the hot midday sun.

There are other options, too. Some products coat solar panels to reduce the need for cleaning. You can also purchase sprinkler systems for solar panels. However, it's important to check your solar panels to make sure they are operating like they should, because you still may need to clean them in certain situations.

Ready to determine whether solar makes sense for your needs? Learn more with Rocket Solar^SM.