Solar Panel Cleaning That
Restores Full Energy Output
London & Surrey

Solar panels generate electricity by absorbing sunlight through their glass surface. Any contamination on that glass — bird droppings, tree sap, pollen, atmospheric dust, lichen or general grime — reduces the amount of light reaching the photovoltaic cells, directly reducing energy output and your return on investment.

Research consistently shows that dirty solar panels in urban environments like London lose between 15% and 30% of their rated output. For a typical 4kW domestic installation generating approximately £600–£900 per year in energy savings and SEG payments, that represents £90–£270 per year in lost income — every year the panels are not cleaned.

Rain does not clean solar panels effectively. While heavy rain washes away loose dust, it leaves mineral deposits, does nothing to remove bird droppings or tree sap, and actually worsens the problem by creating dried watermarks that scatter light. Professional cleaning with deionised (pure) water leaves no residue and restores the glass to factory-clear condition.

We clean residential rooftop arrays, ground-mounted domestic installations, commercial roof arrays, solar farms and agricultural installations. Our deionised water system is safe for all panel types and manufacturers, and our methods comply with the maintenance requirements of all major warranty terms.

Most solar panel owners do not monitor their system output closely enough to notice gradual efficiency loss. Panels become dirty slowly over months and years, and the reduction in output is incremental — a few percent here, a few percent there. By the time the drop is noticeable, you may have already lost hundreds of pounds in potential generation.

Bird droppings are the single biggest performance killer. A single bird dropping on one cell of a panel can reduce the output of the entire panel by 30–40%, because solar panels are wired in series — one blocked cell limits the current flow through the entire string. On a typical residential installation, this means one dirty panel drags down the output of several connected panels.

Tree sap and pollen are common problems in suburban London and Surrey where mature trees overhang rooflines. Sap bonds with the glass surface and bakes on in sunlight, creating opaque patches that cannot be removed by rain. Pollen accumulates in spring and creates a fine film that, while less visible, measurably reduces light transmission.

Lichen growth on panel frames and glass edges is increasingly common on installations over 5 years old. Once established, lichen spreads across the glass surface and bonds aggressively, requiring careful professional removal to avoid scratching the anti-reflective coating.

The financial case for regular cleaning is straightforward: a professional clean costs £80–£200 and recovers £90–£270 per year in lost output. The clean pays for itself within the first year and generates net positive returns every year thereafter.

Recover Up to 30% Output

Cleaning removes the contamination layer that blocks sunlight. Most owners see an immediate measurable increase in generation after professional cleaning.

Warranty-Safe Methods

Our deionised water system uses no chemicals, no abrasive materials and no high pressure. All major panel manufacturers approve this cleaning method within their warranty terms.

No Roof Access Required

Our telescopic water-fed pole systems reach most residential roof arrays from ground level, eliminating the risks associated with roof access and the need for scaffolding.

Spot-Free Finish

Deionised water contains zero dissolved minerals. It dries without leaving the watermarks and mineral deposits that tap water creates — keeping panels cleaner for longer.

Extends Panel Lifespan

Regular cleaning prevents the build-up of corrosive bird droppings and organic acids that can permanently damage anti-reflective coatings and cell connections over time.

Pays for Itself

The cost of cleaning is recovered within months through increased energy generation. Every year after that is net positive return on a simple maintenance investment.

Deionised water (also called demineralised or pure water) is produced by passing tap water through a multi-stage filtration system that removes all dissolved minerals, salts and impurities. The resulting water has a total dissolved solids (TDS) reading of 0–5 parts per million, compared to London tap water which typically reads 250–350 ppm. This purity is what allows deionised water to clean glass without leaving residue.

Our water-fed pole systems use lightweight carbon fibre poles with soft-bristle brush heads, connected to a pure water supply via a flexible hose. The poles extend up to 15 metres, allowing us to clean panels on three-storey buildings from ground level. For higher installations or complex configurations, we use roof-access methods with appropriate safety equipment.

We never use cleaning chemicals on solar panel glass. Chemical solutions — even those marketed as 'solar panel cleaners' — can damage the anti-reflective coatings applied to panel glass during manufacture. These coatings increase light absorption by 2–3% and, once damaged, cannot be reapplied. Our pure water method is the only approach that is universally safe for all coating types.

The brush heads we use are specifically designed for solar panel cleaning — softer than standard window cleaning brushes, with flocked bristle tips that will not scratch the glass surface. We replace brush heads regularly to prevent any accumulated grit from being transferred between panels.

Bird dropping removal requires particular care. Fresh droppings dissolve easily in deionised water. Dried, baked-on droppings require soaking with warm deionised water and gentle agitation — never scraping, which risks scratching the glass. We allow adequate soak time and repeat the process if necessary rather than applying force.

For commercial installations and solar farms, we deploy multiple operative teams with vehicle-mounted pure water generation systems that can process thousands of litres per day. We can clean large arrays on scheduled maintenance contracts, providing before-and-after output data to demonstrate the performance recovery achieved.

We recommend cleaning residential solar panels once per year as standard. Properties with heavy bird activity, overhanging trees or proximity to construction sites may benefit from twice-yearly cleaning. We can coordinate solar panel cleaning with our gutter cleaning service for a combined visit that reduces overall cost and disruption.

Common Questions

Frequently Asked Questions