How can I keep my solar panels clean?

The sunniest months of the year are march – august. On average, these six months will provide 75 percent of the annual solar energy system’s output. Keep your solar panels clean to prevent loss of productivity. The best time to clean them is in March or April. Your panels will then be clean during the sunniest months of the year and you won’t need to worry about a loss of efficiency.

Solar panel manufacturers state that cleaning solar panels is unnecessary because they are cleaned by rain. However, various studies have shown that cleaning the solar panels once a year can prevent a 3% loss of power output. Inspect your solar panels three times a year and pay particular attention to bird droppings, leaves and other stubborn dirt.

When cleaning your solar panels, it is important to pay attention to the following:

  • Clean the solar panels early in the morning or later in the evening. At these times they will dry less quickly and there will be less limescale residue.
  • If your roof is hard to reach and you spot dirt, do not take any unnecessary risks. Use a window wiper with a telescopic handle and try to rinse the solar panels with a garden hose. Telescopic window wipers with garden hose attachments are available.
  • When accessing a pitched roof, always use fall protection gear.
  • Follow the cleaning instructions supplied by the solar panel manufacturer.

Stubborn dirt:

  • First try to remove the dirt without water. If this doesn’t work and you can easily reach the solar panels, use warm water, a special detergent and a soft sponge. Do not use all-purpose cleaning fluid or green soap as these may damage the coating.
  • Do not use scouring agents because these will affect the coating on the glass. It is also unwise to clean the solar panels with a scouring sponge as this will leave scratches on the glass, which will have a negative effect on their performance. Under no circumstances use a high pressure cleaner because water will be forced between the cells in the glass.

Light dirt:

If there is no stubborn dirt on the solar panels and going up onto the roof is hazardous, use a garden hose to rinse them clean. This is a simple way of keeping your solar panels clean. Any dust that settles on the panels will usually come off. If the water in your area is extremely hard, clean your solar panels with rainwater and a soft brush.

See the extensive instructions here