Solar panels are one of the most hands-off improvements you can make to a home or business, and most of the time they quietly get on with the job. Rain does a fair amount of the cleaning for free. That said, panels across the South West do pick up salt, dust, pollen and bird mess, and a little sensible cleaning can protect your output. The trouble is that DIY cleaning goes wrong far more often than people expect, and some of those mistakes cause permanent damage or a nasty fall. Here are the errors we see most often, and what to do instead.

Using Abrasive Tools on Delicate Panel Glass

Panels look tough, and the tempered glass genuinely is. What isn't tough is the anti-reflective coating bonded to it, which helps the panel absorb more light. Scourers, wire brushes, scrapers, dry cloths and stiff yard brooms all scratch that coating away. You won't see it from the ground, but you will notice it in your generation figures over the following years, because scratched panels can't be restored.

Cleaning dry is the related error. On a dusty array in Wiltshire or a salt-caked one in Cornwall, dragging a cloth across the surface grinds grit into the glass. Rinse first, then use a soft microfibre cloth or a proper solar brush on a telescopic pole, with plenty of water to carry the dirt away.

Bird droppings deserve the same patience. They're acidic and worth removing promptly, but soaking them for a minute or two lifts them far more gently than elbow grease ever will.

Reaching for Harsh Chemicals and Household Cleaners

Washing-up liquid, bleach, patio cleaner, vinegar mixes and ammonia-based glass sprays are all tempting, and all best left in the cupboard. Detergents leave a film that attracts more dirt, whilst harsher products can attack the sealant around the panel edges, the anodised aluminium frame and the junction box beneath. Once moisture gets past a compromised seal, you're dealing with water ingress — both a warranty problem and an electrical one.

Plain water is nearly always enough. For stubborn tree sap or heavy coastal grime, a pH-neutral product made for solar panels, used sparingly and rinsed off thoroughly, is fine. Never mix products, and never use anything you'd hesitate to put on your car's paintwork.

Taking Chances With Ladders and Roofs

This is the mistake that matters most. Falls from height are the leading cause of serious DIY injuries, and an array usually sits on a pitched roof with tiles, slate or guttering that are slippery when wet — which, in the South West, is most of the year. Leaning an extension ladder against guttering, clambering onto a damp roof or balancing on a conservatory to reach the last panel simply isn't worth it.

Walking or kneeling on the panels themselves is another risk. The glass flexes under weight, and micro-cracks caused by pressure rarely show immediately but can lead to hot spots and reduced output months later. If your panels are reachable from ground level, a telescopic pole is a sensible approach. Anything higher, steeper or more fragile belongs with someone who has proper access equipment, harnesses and insurance.

Getting the Timing, the Water and the Pressure Wrong

Timing. Cleaning at midday on a hot day is tempting because everything dries quickly, but it's the worst choice. Cold water on hot glass causes thermal stress, and fast evaporation leaves streaks and mineral spots. Clean in the early morning or the evening when the array is cool, skip frosty mornings entirely, and never chip ice or snow off panels.

Water. Hard water is a genuine problem in limestone areas such as Bath, parts of Wiltshire and the Cotswolds. Tap water leaves limescale spots that block light and look dreadful, so filtered or deionised water is far better if you can get it.

Pressure. A pressure washer seems efficient but forces water past seals, can crack cells and lift coatings. Even on a low setting, keep it well away from the panels, mounting rails and roof fixings.

Overlooking the Local Picture: Salt, Soil and Seasons

Conditions vary enormously across the region, and cleaning should reflect that.

• Coastal Cornwall and Devon: salt spray leaves a fine film that builds up quietly, and gull droppings are acidic and corrosive. A gentle rinse every few months pays off.
• Somerset and Dorset: fine red soil and agricultural dust settle after rain and are best rinsed off before they bake on.
• Spring: pollen from April to June coats panels quickly, so a light clean in late spring restores lost output.
• Autumn and winter: leaf litter, moss and storm debris gather around frames and rails, and shading from nearby trees and hedges grows year on year.

Safer Habits and Knowing When to Call in Help

Keep it simple: clean early or late, rinse before you wipe, use soft tools and plain water, and stay firmly on the ground. Check your inverter or monitoring app afterwards — a small rise in generation confirms you've done it properly.

Then watch the things that aren't about cleaning at all. Trim hedges and branches that shade the array in winter. Look for cracked glass, loose cables, damaged mounting clips or any sign of water ingress. Consider bird proofing if gulls or pigeons are regular visitors, and if output drops noticeably for no obvious reason, ask an installer to take a look.

If your panels sit on a roof you can't reach safely, it's no reflection on your DIY abilities to have them cleaned professionally. A proper clean every year or two, timed around your local conditions, is usually all a South West array needs — and it protects your warranty, your yield and your knees.