What should I do if my solar panels are stained or scratched after cleaning?

If your solar panels show stains or scratches after cleaning, act immediately to prevent energy loss and further damage. Here’s a structured guide tailored to UK homeowners and small businesses:

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Immediate Steps

1. Stop using damaged panels if safe to access, especially for scratches that expose wiring. For roof-mounted systems, avoid climbing unless trained.
2. Document the damage with photos and note cleaning methods used. This is critical for warranty claims or insurance disputes.
3. Contact your installer or cleaning service – reputable UK firms like Clean Solar Solutions Ltd or Solar Panel Cleaning Services Ltd often provide post-cleaning inspections and warranties.

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Stains

Common Causes

• Water spots: Hard water residue from improper rinsing.
• Biological growth: Algae/moss in damp UK climates.
• Chemical residues: Harsh detergents reacting with panel coatings.

Solutions

• Mild cleaning mix: Use deionised water with a soft brush (no metal bristles).
• Professional cleaning: Robotic or pole systems (e.g., Xline’s telescopic kits) avoid ladder risks.
• Avoid vinegar/bleach: These can void warranties and degrade anti-reflective coatings.

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Scratches

Risk Assessment

• Superficial: Minor surface marks rarely affect output.
• Deep scratches: Exposed cells risk water ingress and corrosion – common after abrasive cleaning tools.

Repair Options

• Microfiber polishing: For light scratches, professionals may use non-abrasive techniques.
• Panel replacement: Recommended if >10% surface is compromised. Costs vary but start at £150-£300 per panel in the UK.
• Insurance claims: Many UK home policies now cover solar damage if cleaning was professional.

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Prevention

UK-Specific Tips

• Timing: Clean early morning to avoid quick-drying stains in direct sunlight.
• Tools: Use extendable poles with soft brushes (e.g., Solar Panel Cleaning Brushes UK’s equipment) – never pressure washers.
• Frequency: Agricultural businesses in areas like Herefordshire typically clean quarterly due to pollen/manure; urban systems may need biannual cleaning.

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Professional vs DIY

Factor	Professional	DIY
Cost	£1.50-£3.50/panel	£0.50/panel (equipment only)
Risk	Low – insured, SMAS-accredited	High for roof work
Results	Guaranteed stain removal	Variable quality

Don't use universal window cleaners – most degrade solar panel hydrophobic coatings.

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Policy Context

Under the Microgeneration Certification Scheme (MCS), using unapproved cleaning methods can void warranties. Recent (2023) updates require documented cleaning logs for commercial feed-in tariff eligibility.

For businesses: SMAS-accredited cleaners (like Solar Panel Cleaning Services Ltd) help meet CDM Regulations for roof safety audits.

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When to Replace

Consider full replacement if:

• Output drops >15% post-cleaning (measure with inverter data).
• Visible cracks accompany scratches – common after harsh winter cleanings.
• Older systems (10+ years) – newer panels are more scratch-resistant.

For UK-specific advice, consult the BRE National Solar Centre guidelines on panel maintenance.