Does Cleaning Your Solar Panels Make a Difference?

Solar panels are designed to sit outside in all weather conditions, so it is easy to assume that rain will keep them clean enough. In reality, panels can gradually collect dust, pollen, traffic film, bird mess, leaves and general residue over time.

This build-up may not always be obvious from the ground, but it can reduce the amount of sunlight reaching the solar cells. When that happens, your system may not perform as efficiently as it could.

A Real Example

We recently looked at a solar PV system that had been cleaned for the first time in around two and a half years.

Before the clean, the system was reaching a peak generation of around 5.0kW. After the panels were cleaned, peak generation increased to 5.78kW.

That is an increase of around 15.6% in peak output.

Of course, solar generation is affected by several factors, including weather conditions, roof pitch, shading, temperature, panel orientation and the time of year. This means no two days are ever exactly the same, and results will vary from system to system.

However, this example shows that panel cleaning can make a noticeable difference, particularly where dirt and residue have built up over a long period.

Why Solar Panels Get Dirty

Even in the UK, solar panels can collect a surprising amount of dirt. Common causes include:

• Dust and airborne particles

• Pollen

• Bird mess

• Traffic film

• Moss and organic residue

• Leaves and debris around the panel edges

Rain can help wash away some surface dirt, but it does not always remove stubborn marks or residue. In some cases, rainwater can also leave dirt sitting along the lower edge of the panels.

What Are the Benefits of Cleaning Solar Panels?

A professional solar panel clean can help your system perform more effectively by allowing more sunlight to reach the cells. It can also improve the overall appearance of the installation and provide an opportunity to visually check the condition of the panels, fixings and surrounding roof area.

The main benefits include:

• Helping to maximise solar generation

• Removing built-up dirt and residue

• Improving the appearance of the system

• Supporting long-term system maintenance

• Giving a clearer view of the panels and roof area

Panel cleaning is not about guaranteeing a fixed increase for every system. Instead, it is about removing avoidable build-up and giving your solar PV system the best chance to perform properly.

How Often Should Solar Panels Be Cleaned?

There is no single answer that applies to every property. Some systems may stay relatively clean for years, while others may need attention more often due to nearby trees, birds, roads, industrial areas or a shallow roof pitch.

If your panels have not been cleaned for a while, or you have noticed a drop in performance compared with previous years, it may be worth arranging a professional clean.

Need Help Arranging a Solar Panel Clean?

If you are unsure whether your panels would benefit from cleaning, M+S Renewables can help arrange a professional solar panel clean and advise on the best approach for your system.

Keeping your panels clean is a simple way to support system performance and protect your solar investment over the long term.