One of the many advantages of solar panels is their reliability. Their power source – sunlight – is available every day. As long as your panels are good quality and have been properly installed, there should be nothing to stop them working well for decades.
To work at their maximum efficiency, however, solar panels need to be kept clean. If you experience a decline in the amount of electricity your solar panels are producing, it’s probably due to a build-up of dirt and debris on their surface, such as dust, plant sap, lichen and bird droppings.
Why you should clean solar panels?
Solar panels use the sun’s energy to create electricity. They will work whenever the sun is out, but the sunlight needs to be able to reach the photovoltaic cells inside the panels.
This is why you should not install solar panels in the shade – anything which blocks light from getting to part (or all) of the photovoltaic cells will massively reduce a solar panel’s efficiency (and how much electricity it can generate).
Because solar panels are installed on your home’s roof, they will get covered over time in debris like dust, sap, leaves, soot and yes, bird droppings. These will all obstruct the sunlight from reaching the photovoltaic cells inside the panels, and could have a big effect on their output.
With some types of solar panel, even a tiny obstruction can cause a large drop in electricity production, as the few cells that are in shadow can hugely drain the power that the rest of the cells are producing.
In fact, it’s been estimated that not cleaning your solar panels can reduce their performance by as much as 10% to 30%.
When should you clean your solar panels?
The obvious answer is when they look dirty.
But how often is that likely to be? Manufacturers often recommend cleaning your solar panels once or twice a year, but your installer should be able to give you guidance when they fit your panels.
However, if you do notice that your solar panels have become less efficient, this might be a sign that they need a good clean.