Do Solar Panels Need Cleaning?

To clean or not to clean? That is the question regarding solar panels.

Maybe you are one of those who have researched solar and own a system for your home. You are now enjoying the benefits of it as your electricity bill gets slashed to pieces. You tell your friends what a great investment it is to go solar and how it not only affects the environment positively but it reduces your electricity bill significantly.

But maybe you aren’t as aware of the maintenance required to optimize your solar system absorption. There are reasons why cleaning solar panels is extremely beneficial for someone who owns a system.

Cleaning solar panels

Are Dirty Solar Panels Less Efficient?

Yes, dirty solar panels are less efficient than clean ones. Dust, bird droppings, and leaves hinder the solar panels to operate at maximum efficiency.[1] The efficiency rating of the panels is based on the optimal performance of these panels which are adversely affected by general uncleanness.[2] Though SunPower systems have the highest efficiency rating on the market, even these panels can be affected negatively by the buildup of dust or dirt.

How Much is the Output Loss Due to Dirty Solar Panels?

The important thing is to maintain the optimal output of your SunPower system. There can be a decrease of 1.5% to 6% of solar output annually due to collected dust or other particles.[3] This is a very conservative figure as the same study showed that in dustier areas or places with higher pollution the numbers can range between 2% and 50% on conventional solar panels.[4]

The kinds of particles from pollution that drastically hinder the photovoltaic process the most are:

  1. Ash
  2. Calcium
  3. Limestone
  4. Soil
  5. Sand
  6. Silica[5]

All pollution has some form of dust that negatively affects the maximum productivity of solar panels. Los Angeles along with Bakersfield are the cities with the worst pollution in the U.S.[6] This means that dust from pollution affects southern Californians and central Californians the most.

How Dirt & Pollution Can Damage Solar Cells

Not only will dirt and airborne pollutants affect the production of solar panels, but they will also harm the solar cells themselves. A conventional and regular cell shaded by dust gatherings will act as a resistance to the power generated by other cells and this, in turn, causes the shaded cell to heat up and damage the cell.[7].

Many solar systems are not independently connected to a microinverter and rely on the surrounding cells to maintain solar productivity. SunPower cells, however, are all independently connected to the microinverter and the cells around one another are not affected in any way by each other. If one cell were to be shaded or covered in dust, the others will continue working fine without damaging the shaded cell. But the production of that one cell will still be affected by the dust.

Is Rain Enough to Clean Solar Panels?

The National Renewal Energy Laboratory indicated that cleaning solar panels are much more needed in areas with infrequent rainfall, like Southern California. Rain tends to flush out a lot of the unwanted residue sitting patiently and waiting to devour the sunlight headed towards your panels.

“In Southern California, we do not get frequent rain to clean solar panels naturally,” said DJ Schramm, co-founder of Green Convergence and 30-year plus roofer. “So bird droppings, airborne particles from dirt, pollen, and pollution fall out, mix with dew to create grime and slime that reduces the ability of the solar array to perform at full capacity. Dirty panels reduce the return on your investment. We have seen losses as high as 30%.”

Rain, however, is not the cure-all for cleaning solar panels because rain still contains within it “airborne dust particles” that will still leave a layer of dust on the panels. This means that although rain may wash out the old dust on the panels, it brings with it new dirty particles.

How to Clean Solar Panels

Besides all the “dust talk”, let’s assume that you are interested in cleaning your panels by yourself. A lot of solar companies would not recommend that because of safety and liability reasons.[8] To clean your solar panels you would need to ascend to the top of your roof and scrub the panels yourself which can pose a danger to some. Although this may save you some money, it is highly discouraged because of the delicate nature needed in attending those panels as well as the principle of "safety first."

Can You Pressure Wash Solar Panels?

Power washers are good for a lot of things, but cleaning solar panels is not one of them. Pressure washers are too powerful to safely clean solar panels and can end up causing scratches or other damage. If your solar panels are dirty, it's best to use a non-abrasive sponge and soapy water. Better yet, call a professional who can ensure that the job is completed properly and safely.

How Often Should You Clean Solar Panels?

It is generally recommended to clean solar panels every 6 months to a year in order to maintain the productivity, efficiency, and effectiveness of the panels. However, based on where you live and the level of dirt and pollution, the need for cleaning may be more frequent.

Maintain Your New Solar System with Green Convergence!

A SunPower system is a great investment. Once you begin saving with solar, you don’t need to worry about constant maintenance with SunPower’s 25-year warranty - even though overtime we do recommend keeping your panels clean to maximize your highest performance. Investing in a house comes with certain upkeep costs, investing in a car has certain maintenance costs, and investing in a solar system naturally comes with certain polishing procedures.

Don't lose out on efficiency.
Contact SunPower by Green Convergence today get your solar panels cleaned today!


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