What's the most effective and safest way to clean solar panels?

March 14, 2018

Benz Softwash supply softwash chemicals to the professional softwash cleaning trade

A customer asked us about the most effective, and safest, ways to clean solar panels on a roof.

The fact is the majority of solar panels are designed to be self-cleaning, and as such require relatively little cleaning.

However, "self-cleaning" is a bit of a misnomer, like "self-cleaning" windows. For sure they don't need cleaning so frequently ... but they do need regular cleaning to remain efficient.

Quick tip: Grime and bird poo doesn't need to cover an entire solar panel to have a negative effect on it's performance.

In certain situations, such as solar panels mounted in a particularly dry area (allowing dust and bird droppings to build up) or where the solar panel's tilt angle is less than five degrees, most manufacturers recommend regular cleaning to ensure the panels continue to work efficiently.

How to clean solar panels?

Solar  panel manufacturers suggest that using plain fresh water – ideally de-ionised – will be sufficient for cleaning most solar panels most of the time. They also recommend not using detergents that cause streaking and thus compromise the effectiveness of the panels.

Quick tip: In hard water areas it is crucial to wipe all water from the solar panels to prevent limescale/calcium building up.

If you have a window cleaning WFP set-up with de-ionised water, that is the best way to clean solar panels. And of course add a few drops of Benz Window Cleanze to your de-ionised water help remove bird droppings and spider poo. 

Quick tip: Benz Window Cleanze does not leave streaks.

Softwashing a roof that has solar panels

When softwashing the roof with Benz Bio Cleanze or Benz Lightning Cleanze it will be important to ensure the solar panels are not splashed or covered with spray drift. It is highly unlikely that they would be damaged but it's best to be too safe now than sorry later.
The solution is simple: Use a brush for applying the biocides, which will enable you to easily avoid getting biocide onto the solar panels. And of course cleaning the solar panels after soft washing the roof with de-ionised water and Window Cleanze will remove any biocide that may have accidentally got onto them.

Contact the manufacturers of the solar panels

If you are in any doubt about the best way to clean solar panels we suggest contacting the manufacturers of the panels and asking for their advice.

Materials are continually evolving and it would be wise to check that they have not introduced some new substance into the construction of the panels that cleaning could inadvertently compromise.

Quick tip: Get hold of the manufacturer's Product Data Sheets and Safety Data Sheets, which will tell you the recommended ways to clean their products.

Is there a danger of electrocution when cleaning solar panels?

The fact is that solar panels are electricity generating machines and should be treated with the same care and respect due to all electrical equipment. Even a small current passing through your heart can be fatal.

If a contractor does not have a good working knowledge of cleaning electrical equipment safely we suggest sub-contracting the work to a specialist, or getting trained in the required skills and H&S procedures.

How to clean solar panels contaminated with algae?

Benz Bio Cleanze diluted 30-50:1 is a good choice (after checking with the manufacturer of the solar panels that the product would be safe to use).

Simply spray the panel, let Bio Cleanze activate for 30-60 minutes, then agitate with a solar panel WFP brush and de-ionised water (treated with Window Cleanze) to clean the panel.
Use the correct brush: A normal water fed pole window cleaning brush should not be used on solar panels but rather a special one for cleaning solar panels.  We use a "flocked" soft brush, which Gardiners recommended in their solar section.
As always, test a small area of one of the panels, then get your customer's agreement that the result is to their satisfaction and obtain their permission to treat all the panels.

We hope this information about soft washing solar panels is helpful and helps you succeed in your soft washing business.


Ben, Leo & Fiona

PS: Soft washing solar panels is a great market. Think of the many fields of panels that are popping up in fields all over the country, as well those on rooftops. All will need professional cleaning.


Click Here to explore the full range of Benz softwash cleaning products

Benz Softwash Bio Cleanze DDAC biocide & Benz Softwash Lightning Cleanze SH sodium hypochlorite biocide

Leave a comment

Comments will be approved before showing up.

Also in Benz Trade Tips

Softwash chemical application kit
Are pencil jets or fan jets best for soft washing brushes?

July 21, 2021

We use pencil jets in our brushes because we've found they don't clog or break as much as fan jets.

In the case of the Gardiner 45cm brush we use four of them. We turn the pump down so the flow rate is acceptable and does not produce much run-off.

Flow control at the pole is still critical however. Click the link on this page to learn about the solution we've found to be so successful ...

View full article →

Soft washing at heights - your problems solved! (how-to video)
Soft washing at heights - your problems solved! (how-to video)

July 15, 2021

Watch Ben use his innovative pole trigger to safely and efficiently treat wall render. This patent pending trigger enables you to  work more efficiently, with less effort and far less strain on your body. Click the link on this page to watch our how-to video >>>

View full article →

Benz Bio Cleanze, DDAC based softwash biocide
Do you know why we add IPA (Isopropyl Alcohol) to Bio Cleanze?

July 10, 2021

Some customers have wondered why we add IPA (Isopropyl Alcohol) to Benz Bio Cleanze. So we thought we'd clear this up and clarify the situation once and for all.

Click the link on this page to read the full Trade Tips post ...

View full article →