Keeping your solar panels clean
Dirty solar panels lose up to 25% of their efficiency
Solar panels require exposure to direct sunlight in order to produce the most effective electrical output. Dust and pollution settle on the protective glass layer of solar panels resulting in lower total power output. In extreme cases, shade cast by dust spot or other debris can cause hot spots to form on the wafers of the PV panel that can cause fires.
PV Panel hot spots
Hot spots on solar panels appear when an area of the cell exhibits higher electrical resistance. Resistance in the cells convert electrical current to heat which is normally dissipated to the surroundings. Hot spots concentrate intense heat to one area of the cell that could damage the housing and lead to fires.
Don't use soap to clean PV Panels
Newer solar panels are coated with anti-reflective films such as silicon nitride or titanium oxide. These anti-reflective films drastically improve the efficiency of solar panels by reducing the reflexivity of the panel. These films are sensitive to solvents and detergents that can ultimately strip the film from the glass making the panel less effective.
The best way to clean your solar panels is with clean water at room temperature. Do not use hot water and take special care to avoid wetting the electrical contacts of your solar panel.
Don't use abrasive cleaning equipment
Always use a soft window cleaning device to remove stubborn dirt and grime. Sharp or abrasive materials can strip the anti-reflective coating of the solar panels.
Harsh scrubbing equipment like steel brushes may scratch the glass and create shade spots on the solar cells.
Avoid mechanical stress
If your solar array is not ground mounted and not easily accessible, take care to avoid mechanical stressors on the glass and frame of the solar panel.
Do not balance a ladder directly on the frame of the solar panel and if you’re using a telescopic cleaner, take care to avoid impacts to the glass of the panel.
If your solar array is roof mounted be careful not to step or stand on the panel itself as the frame and glass is not designed to withstand such forces.
The best time to clean your solar array is early in the morning or late in the afternoon. During peak hours, the solar panels and glass become very hot, and spraying water on the panel may cause thermal stress and break or crack the glass.