How do I know if my solar panels need cleaning?

Key indicators your solar panels may need cleaning:

1. Noticeable energy output drop: Compare current electricity generation against historical performance data (typically accessible via your inverter or monitoring app). Even a 10-15% reduction could signal dirt buildup.
2. Visible dirt/debris: Bird droppings, pollen, or lichen streaks (common in UK coastal regions) creating patchy shading.
3. Post-storm checks: After heavy winds depositing leaves/twigs or Saharan dust events (increasingly frequent in southern England).
4. Seasonal changes: Spring pollen (March-May) or autumn leaf fall requiring extra attention.

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Solar Panel Cleaning Systems Explained

DIY vs Professional Cleaning

Aspect	DIY	Professional
Cost	£0-£50 (water/soft brush)	£100-£300/year
Safety	Risk of roof falls; void warranties if improper tools used	Insured, height-certified technicians
Effectiveness	Suitable for light dirt	Removes stubborn grime (cemented bird droppings)
Equipment	Hose, soft brush, purified water	Deionised water systems, robotic cleaners

Common DIY mistakes to avoid:

• Hard water stains: Use purified water to prevent mineral deposits.
• Abrasive tools: Never use pressure washers or stiff brushes.
• Timing errors: Early morning cleaning risks thermal shock from cold water on hot panels.

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When to Choose Professional Systems

1. Complex roof access: Steep pitches or 3+ floor buildings.
2. Commercial-scale arrays: Systems over 10kW benefit from robotic cleaners (e.g., SolarCleano).
3. Biological growth: Specialised treatments for moss/lichen common in Wales and Scotland.

UK-specific considerations:

• Rainfall paradox: While UK rain helps rinse panels, it worsens "cementing" of bird droppings.
• Planning restrictions: Some conservation areas require specific cleaning methods.
• New build trends: Integrated cleaning systems becoming common in new solar installations (2023-2025).

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Maintenance Best Practices

Monitoring tools:

• Free apps: MyEnlighten or Solax Cloud for real-time performance tracking.
• Physical checks: Bi-annual inspections during daylight savings clock changes.

Cost-saving tip: Schedule professional cleaning during March/April to optimize summer output when sunlight intensity peaks.

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Essential checklist:
✅ Compare energy output monthly
✅ Visually inspect after extreme weather
✅ Clean only when necessary (1-2x/year typically sufficient)
✅ Consult installers about integrated cleaning accessories
✅ Check warranties - some require professional maintenance.