One of the many benefits of solar panels is that they need very little maintenance. That said, if you want to get the most out of them, you’ll need to give them a little TLC now and again by cleaning them. You can hire a pro to tackle the job or climb on the roof and do it yourself. You only need a garden hose with a sprayer attachment and a little dishwashing liquid to clean solar panels. Here’s how to clean solar panels to keep them at peak efficiency.
Key takeaways:
Dirty solar panels may not produce as much energy, so cleaning them is a must.
As a rule of thumb, clean your solar panels every six months.
A soft brush, warm water and dish soap are all you need to clean solar panels.
When in doubt, call a professional. Professional solar panel cleaning is often only $20 per panel.
Do I need to clean my solar panels?
While not cleaning solar panels won’t damage them, it will make them less efficient since a solar panel works by taking in sunlight and converting it to energy. The impact isn’t huge, but it is significant, said Oliver Richards, founder of UK solar installer Total Solar Solutions.
“Due to particles like dust, pollen and the occasional unpleasantries delivered by our feathered friends, the system will build up a layer which can slightly reduce the efficiency of the panels by about 7%.”
Automatic cleaning systems
One alternative to cleaning your solar panels yourself or hiring someone to clean them is installing a cleaning system that automates the job.
These systems have small spray nozzles that connect to each panel. Automatic cleaning systems operate in two cycles: a wash cycle that covers the panel in biodegradable soap explicitly designed for solar panels and a rinse cycle that cleans the soap off. Like a lawn irrigation system, you program how often you want the automatic cleaning system to clean the solar panels.
“Sometimes, a specialized cleaning robot or hiring a professional service makes more sense than a DIY approach, especially if you’re dealing with a larger setup or hard-to-reach panels,” said Daniel Espada, a product and project manager at Solar Cleaning Machinery, a company that manufactures solar panel cleaning robots for large solar arrays.
While these systems make cleaning convenient, they’re expensive. Depending on the size of the solar array, expect to pay around $2,300 for an automatic cleaning system.
8 steps to clean solar panels
1. Check the manufacturer’s cleaning guidelines.
It’s always a good idea to check the solar panel manufacturer’s cleaning guidelines before cleaning the solar panels to avoid potentially damaging them.
2. Time your cleaning effort.
Avoid cleaning when it’s hot outside, as spraying hot panels with cold water can crack the tempered glass. Instead, clean them early in the morning or evening or wait until cooler weather.
3. Gather materials and take safety precautions.
Richards recommended saving money by using simple tools and materials you probably already have lying around the house to complete the job. Just be prepared for a workout. “If your intention is to DIY and get this done using the most cost-effective methods, I would advise a telescopic soft brush, a generous amount of dish soap, warm water and brace yourself for a great shoulder workout,” he says.
Climbing onto your roof is inherently dangerous, so take common sense safety precautions to minimize the risk of injury. Wear work boots that will give you good traction on the roof shingles, and find a helper to hold the ladder as you climb up and down it.
4. Turn off your solar system.
Don’t start cleaning until you’ve cut power to the solar system to eliminate the threat of electric shock. Consult the solar panel manufacturer’s instructions for how to shut off power to the system.
5. Rinse and scrub the panels.
Start by spraying the panels down using a garden hose with a sprayer attachment to get rid of any leaves, pollen or other dirt that’s collected. Using a brush with a pole extension, gently scrub away any dirt accumulated on the panels. A water rinse and light brushing are often all that’s needed to clean the panels.
6. Apply cleaning solution to problem areas.
If water alone doesn’t clean your solar panels, use a mild soap solution, such as dishwashing liquid mixed with water. Also, resist the urge to apply elbow grease to the panels.
“Harsh chemicals are a no-go — they can cause more harm than good,” said Espada. “And too much weight or pressure can lead to damage.”
Apply the water and dishwashing liquid solution to the panel and gently scrub using your soft-bristled brush. Then, rinse the panels thoroughly.
7. Squeegee the panels dry.
After rinsing the panels, use a squeegee to remove excess water and prevent streaking on the surface that can block sunlight. If you don’t have a squeegee, use a soft cloth to dry the panels.
8. Restart the solar system.
After you’ve finished cleaning and drying the panels, it’s safe to power them back up.
How often should I clean my solar panels?
How often you should clean your solar panels depends on the weather where you live. Richards recommended cleaning them once every six months.
However, if nearby trees dump debris on your roof or you live in a dusty area, you may need to clean them more often. “In high-dirt zones like deserts, snowy regions, coastal areas or near industrial activity, monthly cleaning is your best bet to maintain a solid performance ratio,” Espada said.
Tips for cleaning solar panels
Here are some additional tips to get the most out of cleaning your solar panels:
- Clean solar panels in the spring. Fall and winter tend to leave significant dirt and leaves on solar panels. Time your cleaning for the spring to ensure you get the most out of them during the warmer months.
- Let the solar panels tell you when they need cleaning. Monitoring your solar panels’ performance is one way to determine how often they need cleaning. If their efficiency is low, it might be because there’s too much dirt on them. “Keep a close eye on your panels’ energy output to tailor a cleaning schedule that suits your specific situation,” Espada said.
- Don’t use a pressure washer. While you may be tempted to use a pressure washer to clean your solar panels, resist the urge. A pressure washer can damage the panels and risk damaging your roof. “Pressure washing is like bringing a bazooka to a pillow fight — overkill and risky for your panels,” Espada said. “Stick to gentle cleaning methods; your panels are tougher than you think, but they don’t need a high-pressure blast.”
When to call a professional
While you can clean your solar panels on your own, there are situations where it’s best to call in a professional. In addition to personal safety risks, you risk damaging the solar panels or even your roof by cleaning them yourself.
If you don’t feel confident you can clean your solar panels without causing damage, are uncomfortable climbing a ladder or are unsure about cutting power to the solar panels, don’t risk it. Hire an experienced solar panel cleaning professional. Additionally, if your roof is very high off the ground or has a steep pitch, you’ll need the skill of a pro to clean your panels safely.
“Professionals enter the picture when safety and expertise are paramount,” Espada said.
“If your panels are high on a rooftop or you’re managing a solar farm without the right gear, it’s time to call in the pros.”
You can expect to pay around $20 per solar panel for cleaning. Given that most homes have about 20 solar panels, plan on spending around $400 for cleaning.
Bottom line
If ascending a ladder and climbing around on your roof doesn’t bother you, then you can handle an annual cleaning of your solar panels using tools and items you already have around your home. And while the solar panels on your roof won’t stop working if you leave it to Mother Nature to clean them, you can keep them at peak performance by regularly cleaning them.
