The answer
Do panels need annual cleaning?
Solar panels need monitoring and occasional inspection, but an automatic annual clean is not necessary for every roof. Clean only when soiling is likely to affect output, and use a safe method appropriate to the installation.
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How can you tell whether output is normal?
Keep owner access to the inverter or monitoring portal and save the installer's original generation forecast. Daily output swings with cloud cover and season, so compare similar months or similar weather rather than a sunny day with a dull one. A repeated inverter fault, a sudden sustained drop or one underperforming string is a better reason to investigate than an ordinary winter dip.
Compare generation with your electricity bills too. A lower bill does not necessarily prove the panels are producing well if your household use has changed; likewise, a higher bill may follow a new EV or heat pump. Note major changes in use, shading or equipment settings when reviewing performance.
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Do panels need regular cleaning?
Rain often removes ordinary dust from pitched panels. Cleaning may make sense where bird fouling, nearby trees or industrial deposits cause persistent soiling, but the expected gain should justify safe access and cost. Do not climb onto a roof or use an unsuitable cleaning method to chase a small theoretical yield increase.
If performance drops, check the monitor and visible condition from a safe position before paying for a clean. Soiling is only one possible cause: inverter faults, new shade and electrical issues can have similar symptoms. A targeted inspection is more useful than automatically booking an annual wash.
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What else needs attention over the system's life?
The array includes an inverter, isolators, cables, electrical protection and roof fixings. Keep handover documents and warranty terms where you can find them. Follow the manufacturer's maintenance schedule, and ask a competent installer to investigate damage, water ingress, loose cabling or repeated faults rather than attempting DIY electrical or roof work.
If roof repairs are planned, speak to the solar installer before scaffolding is arranged. Safe isolation, panel removal and reinstatement can affect the programme and cost. For a business site, record who owns the system and who is responsible for monitoring it after staff or tenants change.
Where this guidance comes from
Check the original guidance.
These primary sources support the technical or scheme points above. Rules can change; follow the current source before making a commitment.
Apply this to your property
Concerned about an existing array?
Tell FLO what the monitoring shows and what has changed. A targeted check is more useful than paying for routine cleaning without evidence.