How can I tell if my Solar Panels are dirty?

If they look dirty…they are dirty.

However, for a variety of reasons solar panels can “look” clean, and still be dirty enough to reduce efficiency. Looking clean doesn’t necessarily mean they are clean.

Airborne dirt comes from a variety of sources like bird droppings, dust, leaves, etc.. This is compounded by the fact that solar panels are usually mounted in a near-horizontal position.

Why should I keep my solar panels clean?

The National Renewable Energy Laboratory and other sources estimate that solar array efficiency can be reduced by 20%, or more, if the panels are allowed to get dirty.

In some cases, the panels can even be permanently damaged by dirt and debris.

In order to get all the energy you paid for from your photovoltaic system, the panels must be kept clean.

How often should my solar panels be cleaned?

If your solar array is well away from trees, the ocean, and any other contaminant source, cleaning can be done every 2 to 4 months.

If the solar system is near any significant source of contaminants, monthly cleaning may be required.