Solar panels sit on your roof all year round, exposed to the elements.
Surely, they’re going to get dirty?
The prospect of having to clean your solar panels at height can be off-putting for prospective buyers.
The good news is that most domestic solar panels are very low-maintenance. In many cases, rainfall does a perfectly good job of keeping them clean enough to operate efficiently.
Still, dirt, pollen and bird droppings can occasionally build up over time, reducing how much sunlight reaches the panels. While cleaning isn’t something most solar panel users need to worry about often, it’s useful to understand when it might be worth paying attention to.
How does dirt build-up affect solar panel performance?
In order for your solar panels to generate electricity, sunlight needs to hit the photovoltaic cells inside them. Anything that blocks the light from reaching them can reduce how much electricity the panel produces. In the UK, the most common causes of build-up on solar panels include:
- Dust and general air pollution
- Pollen (especially noticeable during spring and early summer)
- Leaves or organic debris from nearby trees
- Bird droppings
- Moss or algae growth (common on more shared roofs)
Rainfall is usually enough to wash away a light dust layer, but thicker, stickier deposits, like bird droppings, can block a portion of the panel, reducing its output. If you notice a drop in energy production, this could be to blame.
How often should I clean my solar panels?
For most homes in the UK, solar panels don’t require regular cleaning.
Panels are installed at an angle, which allows water to run off and carry dust and dirt away. In many cases, you could go years without needing to clean your panels at all.
However, there are some situations where occasional cleaning may help:
- If you live near trees that drop pollen or sap
- If your solar panels are exposed to high levels of dust or pollution
- If birds frequently perch or nest in nearby trees
- If your solar panels are pitched at a shallow angle, where water can’t run off so easily
Even then, cleaning is usually something you might consider every year or two, rather than every few months.
How to tell if your solar panels need cleaning
A few indicators that your solar panels need cleaning include:
- Visible dirt – If you can see bird droppings, heavy pollen build-up or leaves sitting on the panels, it may be time for a clean.
- A noticeable drop in energy output – Many solar systems include monitoring apps that show how much electricity your panels generate each day. If production drops unexpectedly during sunny weather, dirt could be a factor.
- Streaky or smeared glass – Rain can make things worse if there’s already a layer of dust or grime on the panels. Instead of washing it away cleanly, the water moves the dirt around, leaving streaky residue that can be just as obstructive as the original build-up.
- You’re near a known source of dirt – If you live close to farmland, a busy road or an industrial area, your panels are likely picking up more airborne particles than average. In these situations, it’s worth checking the surface more regularly, as the grime can accumulate faster than you’d expect.
- It’s been a long time since the last clean – If you can’t remember the last time your panels were cleaned, that’s probably a sign in itself. Even without obvious visible dirt, a film of dust and pollution can build up gradually over months, quietly reducing your system’s output without any dramatic warning signs.
Of course, other factors such as seasonal changes or cloudy weather can also affect generation, so it’s always worth checking before assuming cleaning is the issue. If there’s been a long period without rain, it may also be time to give your panels a quick clean.
Can you clean solar panels yourself?
In some cases, it’s possible to clean your solar panels yourself. If you’re considering doing this, safety should always come first.
Solar panels are usually installed on roofs, which means working at height. That carries obvious risks.
If you do attempt light cleaning, some general guidelines include:
- Use clean water and a soft brush or sponge
- Avoid abrasive tools that could scratch the panels’ surface
- Never use harsh chemicals or pressure washers
- Clean panels during cooler parts of the day
Importantly, you should never climb onto a roof unless it’s safe to do so and you have the proper equipment. For most of us, it’s simply easier and safer to leave cleaning to professionals.
When to opt for professional cleaning
Professional solar panel cleaning services may come with an added expense. Still, they have the right equipment to do the job safely and effectively, protecting you (and your solar panels) from damage or injury. You may want to consider professional cleaning if:
- Your solar panels are difficult to access safely
- There’s a significant build-up of debris or bird droppings
- You want the system inspected at the same time
- Your installer recommends it as part of maintenance
Your warranty is another factor to consider. Some manufacturers advise against certain cleaning methods, and using inappropriate tools or chemicals could potentially invalidate your warranty.
Professionals also understand how to clean panels without risking damage to the surface or electrical components, helping to avoid that risk.
Solar panels are designed to be low-maintenance
One of the advantages of solar panels is how little day-to-day maintenance they require. Once installed, they quietly generate electricity whenever daylight reaches them. For most homes, rainfall will handle the majority of cleaning. Occasional checks for debris or unusual drops in performance are usually all that’s needed.
If you’re ever unsure whether your panels need attention, the best approach is to get advice from a qualified installer. At Electrical Innovations, we’re always happy to help you check your solar system and make sure everything is in great condition and performing as it should. If you’d like advice about panel maintenance, cleaning or system performance, get in touch with our friendly team in Derby for a chat.
