Everything You Need to Know About Cleaning Solar Panels

Solar panels require direct exposure to sunlight to function.

The better the sunlight exposure your solar installation gets, the greater amount of energy is produced.

So it is reasonable to hold a grudge against dirty solar panels when your profits are shaded by dirt and dust.

We will share some tips about cleaning solar panels and how you can keep solar production high with minimum efforts.

What Causes Dirty Solar Panels?

Solar panels become dirty over time as they are exposed to dust and pollutants floating in the air.

Dust can build up on PV modules even more quickly if the installation is close to industrial complexes or construction sites.

Solar installations on farms are also known to accumulate fertiliser and nitrogen-rich particles that can gradually corrode solar components.

Bird poop is also a notorious source of shade that not only reduces energy production but can also cause hot spots on solar panels.

How Much Can Cleaning Solar Panels Impact Energy Production?

Depending on how filthy the panels are, cleaning solar panels can improve energy production by 5-10%.

Quick calculations will show that cleaning small residential systems would only improve your energy bill by tens of dollars, so you might as well leave it to rainwater to rinse the solar panels on your angled roof.

But a 5-10% lift in energy production can move the needle on commercial and utility-scale solar farms, and those are situations where you might consider a regular PV panel cleaning schedule or even hiring professional panel cleaners.

When Do You Need to Clean Your Solar Panels?

It is best to clean your solar panels when they get dirty enough to make a dent in energy production.

With the most advanced monitoring systems available with microinverters and power optimisers, you can easily compare panel-level outputs to pinpoint soiled panels or when the whole system is producing less-than-expected energy production.

Flat-installed solar modules are also known to be resistant to self-cleaning with rainwater, as the water settles on the panels to leave behind dirt.

Google found cleaning the flat solar panels installed on carports can improve energy production by 36%.

What Are the Best Ways to Clean Solar Panels?

Whether you are a seasoned solar panel cleaner or a residential solar system owner, you need the right tools to clean solar panels efficiently and safely.

A water hose from ground-level can work wonders in most cases

Rinsing rooftop solar from the ground-level with a hose is the safest cleaning method in most cases.

The water spray should fall on the solar panels like rainwater and let gravity do the heavy lifting.

When bird poo proves to be a tough opponent to your man-made shower, be patient.

A second or third pass of the water hose should remove most of it after the bird dropping has been softened by the water.

Staying on ground-level also means there is less risk of falling.

Use isopropyl alcohol to clean stubborn stains

If you are able to safely climb up the roof for a closer wash, you can use isopropyl alcohol to clean oily smudges without leaving any mark.

We don’t recommend detergent or soap to clean stubborn stains, as they tend to leave residue on panel glass that can attract more dirt in the future.

Make sure you do not stand on the solar modules under any circumstance.

Any pressure on the solar panels risks creating microcracks that can reduce energy output.

Use soft brushes and plastic scourer to make short work of scum

Only brushes specifically designed for solar should be used with water to scrub panels clean of dirt.

Unsuitable scrubbing equipment like a steel brush may scratch the solar glass and create shade that harms solar production.

A plastic scourer can be used to remove caked-on scum after it has been softened with water first.

Finish up with squeegee to prevent water streaks

In the same way that squeegees should be used to finish off a clean window, squeegees can wipe solar panels dry to prevent water streaks from shading solar panels.

WINAICO Solar Panels Have Unique Water Grooves to Drain Rainwater Easily

A good way to facilitate solar panel self-cleaning through rainwater is by using WINAICO’s unique WSP frames.

The WSP corner keys have specially designed drainage grooves to make sure dirty water can run off smoothly and quickly to keep rooftop solar panels clean and maintenance-free.