Cleaning solar panels

How, and how often, should I clean my solar panels?

Installer from Dijkman Zonne-energie in a safety harness placing a black solar panel on a roof next to scaffolding

Clean panels catch more sunlight, so we would advise checking them for dirt now and then, because dirt lowers the yield. Our adviser Ruben tells you everything about cleaning solar panels. And did you know a home battery or an energy management system raises your yield further? Read on, or book a no-obligation consultation straight away.

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When should I clean my solar panels?

First of all it helps to know that panels come with a coating that protects them from dirt. Cleaning them straight away takes that coating off, so we would advise leaving them for the first three years. After that you can check once a year whether a clean is needed.

Get more out of your storage: a home battery stores surplus energy so you can use it when you need it. Read more about home batteries.

So when should you clean them? The clearest sign is a falling yield, which you will see in the app on your tablet or phone.

You can also simply look at the panels. Rain washes most of the dirt away, but bird droppings, green growth, stuck leaves or a layer of Sahara dust do not always rinse off. That can cost 2 to 5% of the yield, because the panels catch less sunlight.

April is the best time to clean your panels, because it is the start of the sunny period that brings about 75% of the yearly yield. Clean panels give you the most out of it.

How often should I clean my solar panels?

We would advise checking your panels regularly for dirt, bird droppings and leaves, and particularly after a spell of Sahara dust or snow. In principle a yearly clean is enough.

If you live near a busy road or an industrial estate, it is wise to clean them more often. After a long dry spell in particular, dirt and dust can build up and lower the yield. Do you live among trees? Then green growth can appear.

Cleaner in an orange vest and yellow helmet cleaning solar panels on a tiled roof with a long brush

Cleaning your solar panels yourself

You can have your panels cleaned by a specialist company, or do it yourself. Good preparation is half the work, so here are a few tips for cleaning them:

Two storks standing on a row of solar panels with bird spikes under a blue sky

If you have to go on the roof to reach the panels, do it safely, with fall protection for instance.
Switch the system off before you clean, and do not touch the cabling.
Use a garden hose to rinse the panels. A pressure washer is out of the question, because it can damage them.
Cleaning panels with tap water sounds sensible but does not give the best result. Rainwater or lime-free water is better, because it leaves no chalky film behind.
Clean your panels in the morning or the evening. In full sun they can get very hot, which leaves marks if the water dries too quickly and can burn you if you touch them.
Use only lukewarm water and a soft sponge or cloth.
Work carefully, and never lean or step on the panels. That can cause microcracks, which make them perform less well.

There are also a few things you should not do when cleaning panels yourself, so as not to damage them:

Cleaning panels with car shampoo, washing-up liquid, all-purpose cleaner or soft soap is a bad idea, because those attack the protective coating. Is the dirt stubborn and do you need a cleaning agent? Then use one made for solar panels.
Avoid scouring agents, scouring pads and scrapers. They damage panels and leave scratches.

Having your panels cleaned

We can imagine you would rather not climb on the roof to wash your panels. In that case a professional company is an idea. Some window cleaners will do them while they are there, and other cleaning firms take the work on as well. There are even companies that do nothing but clean solar panels: they have the right equipment to reach them easily and the right cleaning agents, they know how to get on a roof safely, and they know panels have to be handled with care.

Close-up of bird droppings on a dark blue solar panel

What does having panels cleaned cost?

If you decide to have your panels cleaned, it is worth considering the cost, which varies. As we said, there are different kinds of company, and it also depends on whether you have your windows done at the same time and on how many panels you have. On average the price is between 70 and 110 euros per clean.

Max Control

Curious what your panels produce before and after a clean? Discover Max. Through a handy app, Max Control gives you a detailed view of what your panels and your other sustainable systems generate.

J.Boerman 9

“De installalatie keurig volgens offerte en tijdsplanning snel en vakkundig aangebracht.”

Panels cleaned but the yield still different?

Then request a consultation with Ruben.

Ruben is an adviser at Dijkman Zonne-energie and is happy to answer all your questions about solar panels. A consultation can be online, by phone or at your home.

Request a consultation No obligation!

Ruben, adviser at Dijkman Zonne-energie — **Ruben** Adviser

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