How to Clean Solar Panels on Roof

Solar panels have become an increasingly popular choice for UK homeowners, providing renewable energy and reducing electricity bills. To keep them performing at their best, regular maintenance is required. One of the most important tasks is cleaning. Dust, bird droppings, pollen, and leaves can reduce efficiency by blocking sunlight. Knowing how to clean solar panels on the roof safely and effectively helps ensure long term performance while avoiding unnecessary damage.

Why Cleaning Solar Panels Matters

Solar panels are designed to capture sunlight and convert it into energy. Anything that reduces light reaching the cells affects efficiency. A thin film of dirt may not have much impact, but heavy build up can lower output by 20 per cent or more. In the UK, rain helps to wash away some surface dirt, but it is rarely enough to keep panels spotless all year round. Areas near trees, busy roads, or where birds roost are more prone to dirt build up and therefore benefit most from regular cleaning.

Safety First

Cleaning solar panels on a roof presents safety risks. Climbing onto the roof is not recommended for most homeowners, as panels are often placed on pitched surfaces at height. Attempting to walk on the roof or the panels themselves can lead to accidents or costly damage. For this reason, it is advisable to use telescopic cleaning equipment from the ground or a stable platform. Professional cleaning services are often the best option for difficult to reach panels, as they use specialist equipment and safety systems.

Best Time to Clean Solar Panels

Solar panels should ideally be cleaned during cooler parts of the day, such as early morning or late evening. This is because panels can become very hot in direct sunlight, and cleaning them while they are hot can cause streaking or thermal stress. Cleaning in mild weather also helps water and cleaning solutions dry evenly.

Cleaning Methods for Solar Panels

The key to cleaning solar panels is to be gentle. Abrasive tools or strong chemicals can scratch the glass surface and reduce efficiency permanently. For most homeowners, the following approach is suitable:

• Use a soft brush or sponge attached to a telescopic pole.
• Rinse panels with clean water, preferably purified to reduce streaks.
• Apply mild soapy water for stubborn dirt, then rinse thoroughly.

Always avoid pressure washers, as the strong jet of water can damage seals and force water into the electrical components. Similarly, harsh detergents should not be used, as they can leave residues that attract more dirt.

How Often Should Solar Panels Be Cleaned?

The frequency of cleaning depends on location. In rural areas with little air pollution, once a year may be enough. In towns and cities, or near main roads, cleaning may be required twice a year. Panels under trees or in areas with frequent bird activity may need checking more regularly. Homeowners can often monitor performance through their solar system’s monitoring software. If output drops noticeably compared to previous periods with similar weather, it may be a sign that cleaning is required.

Professional Solar Panel Cleaning

For many homeowners, using a professional cleaning service provides peace of mind. Professionals use water fed pole systems with soft brushes and purified water, leaving panels streak free without chemicals. They also have the training and equipment to work safely at height. The cost usually ranges between £50 and £150 depending on the number of panels and access requirements. While this is an added expense, it helps maintain energy efficiency and can be more cost effective in the long run.

Additional Maintenance Tips

Although cleaning is important, it is only one part of solar panel maintenance. Homeowners should also ensure that surrounding trees are trimmed back so branches do not shade or drop debris onto the panels. Gutters and roof areas near the panels should be kept clear to prevent leaves and dirt being blown onto the surface. During winter, panels generally do not need de icing, as snow usually melts and slides off quickly due to the smooth surface. Attempting to remove snow manually can cause more harm than good.

Do You Need Permission to Clean Solar Panels?

In most cases, cleaning solar panels does not require planning permission or additional approvals, as it is considered routine maintenance. However, if scaffolding is required in a public area, a licence may be needed from the local council. Listed buildings and properties in conservation areas may have additional rules about modifications, but cleaning itself is usually permitted without restrictions.

Conclusion

Cleaning solar panels on a roof is an essential part of ensuring they perform efficiently. While light rain helps, it cannot replace a proper clean. Using soft brushes, mild solutions, and purified water is the best approach, while avoiding harsh chemicals and high pressure tools. For many households, professional services offer a safe and effective solution, particularly for panels installed on high or steep roofs. With regular care and attention, solar panels will continue to generate clean, reliable energy for decades.