If you’re researching
“Do solar panels need cleaning?”
The short answer is sometimes – but not as often as you might think. In the UK climate, rainfall naturally removes most surface debris. However, in certain conditions, solar panel cleaning can improve performance and protect long term efficiency.
This guide explains:
- Whether solar panels need cleaning in the UK
- How often you should clean them
- What affects solar panel performance
- Safe cleaning methods
- When to call a professional
Do Solar Panels Need Cleaning?
For most South East homeowners, solar panels are largely self-cleaning due to regular rainfall. However, cleaning may be necessary if you live near trees, are close to farmland or in coastal areas. If during a routine visual inspection you notice a visible dirt buildup or you see a measurable drop in solar generation, this may also indicate you need to clean your solar panels.
In standard residential settings, panels may only need inspection and possible cleaning every 2-5 years.
Does Dirt Really Affect Solar Panel Efficiency?
Yes – but usually only when buildup is significant. Light dust has minimal impact, however, heavy soiling such as bird droppings, moss or pollution film can reduce light absorption and create “hot spots”. System output will be lowered overall and long term performance will be impacted. On average, heavy dirt can reduce output by 5-20% depending on severity.
If you’re monitoring your system and notice unexpected generation drops – especially outside seasonal variation – cleaning could help restore performance.
How Often Should Solar Panels Be Cleaned?
There is no universal schedule. Instead, cleaning frequency depends on:
| Property Location | Suggested Inspection Frequency |
| Urban areas | Every 2–3 years |
| Rural / farmland | Every 1–2 years |
| Near trees | Annually |
| Coastal areas | Every 1–2 years |
At SolarTherm UK, we recommend regular visual inspection to indicate when routine maintenance checks or cleaning is required.
How to Clean Solar Panels Safely
Safety is critical. Most domestic solar systems are roof mounted, meaning cleaning involves working at height.
Never:
- Use pressure washers
- Use abrasive sponges
- Walk directly on panels
- Climb onto your roof without proper safety equipment
Safe Cleaning Method (If Accessible from Ground Level)
If panels are reachable from ground level or a safe platform:
- Use lukewarm water
- Use a soft sponge or microfibre cloth
- Avoid detergents, unless manufacturer approved
- Clean early morning or evening to avoid hot glass surfaces
When to Hire a Professional Solar Panel Cleaning Service
Professional cleaning is recommended if:
- Panels are on a pitched roof
- There is heavy moss or dirt
- Bird fouling is extensive
- Access requires specialist equipment
Professional technicians use:
- Deionised water systems
- Soft brush telescopic poles
- Safe working at height procedures
This ensures no damage to panel coatings or frames.
Will Cleaning Void My Solar Panel Warranty?
In most cases, you warranty will remain intact provided you follow manufacturer guidelines, use no harsh chemicals or abrasive cleaners and your panels remain free from physical damage. Always check your system documentation before undertaking DIY cleaning. If your installation was carried out by an MCS certified installer, your system will have been designed for minimal maintenance.
Do Solar Panels Need Regular Maintenance?
Solar panels have no moving parts, which means maintenance requirements are low. However, at SolarTherm UK we recommend, regular monitoring of your inverter app or monitoring platform, check annual system performance, check for any changes to shading and check your inverter and wiring for any damage or wear and tear. Routine visual inspections protect your investment and ensures any issues are spotted early and down time is minimised. At SolarTherm UK, we recommend a professional system test every 5 years to ensure your system is running safely and at full efficiency.
Signs Your Solar Panels May Need Cleaning
Look out for visible bird droppings, streaking or thick dirt patches, lower than expected generation or uneven output across panel strings. If unsure, performance monitoring apps can provide useful data comparisons.
The Bottom Line: Do Solar Panels Need Cleaning?
For most UK homes rain does most of the work and solar panels require infrequent professional cleaning or intervention. Safety should always come first, so if your solar panels are mounted on a pitched roof, always contract cleaning to a professional, experienced company. Solar panels are designed to be low maintenance, but periodic inspection ensures maximum efficiency and longevity.
Ready to Find Out More?
If you are looking to find out how much you can save with a solar PV and battery system, try our Solar Calculator.
Smart solar starts with the right advice.
FAQs
Do solar panels need cleaning every year?
Not usually. In most UK locations, inspection is more important than annual cleaning.
Can I clean solar panels myself?
Only if safely accessible. Roof access without proper equipment is not recommended.
Does rain clean solar panels properly?
Yes — for light dust and pollen. Heavy soiling may require manual cleaning.
How much does solar panel cleaning cost in the UK?
Costs vary by system size and access, but typically range between £100–£300.
