Like your car that needs a regular oil change and service to maintain its operational condition, solar panels also need to be cleaned regularly to maintain the efficiency of the supply and prolong your PV system’s life. It makes sense to maintain it as you would with any reasonable investment.
Based on the environment you live in, you may need to clean your solar panels once a month or only once every six months, especially if there is dust, have trees that drop leaves, and have many birds in your area as they are one of the biggest threats to your PV system’s sustainability.
There are areas regarding cleaning solar panels that you need to address :
- What causes solar panels to get dirty
- How much energy you could lose if you don’t clean your panels
- What to use when cleaning solar panels
- When to clean solar panels
A Quick Overview Of Solar Panels
Before we look at that, let’s recap what solar panels are made of and how they generate electricity for your home. Solar panels are made from silicon (sand) and layered in silicon wafers with a conducting material (usual boron).
The wafers are then compacted into a matrix configuration and glass added with an anti-reflective coating that encourages the absorption of sunlight. Electricity is generated as the silicon looks to balance its electrons as the sunlight strikes the panel.
That is a very simplified version, but the point is that the glass and the coating are critical to ensure the panels’ efficacy, which is why they need to be cleaned regularly.
What Causes Solar Panels To Get Dirty?
Since most solar panels are installed on the roof and at an angle to achieve optimum solar exposure, dust, dirt, leaves, and bird droppings can accumulate on the panels over time.
There is an argument that they would be cleaned after each rain, which is true, but if rain was an effective cleaner, car washes would be out of business during the rainy seasons!
Flat solar panels would need more cleaning and maintenance than the tilted ones as they would not benefit from the rain washing the debris off.
This is because rainwater has fine dust that is dissolved and then left behind when the water evaporates. If you have ever just washed your car and had it rain, you will see that fine layer of dust on your windows afterward.
If you live by the coast, the saltwater vapor that settles on everything will also settle on your panels and you’d need to clean them possibly every month to maintain the level of light absorbed.
The same happens with solar panels, and while you may not think that this could reduce the operational efficiency of your solar panels, that’s not entirely true either.
How Dirt, Dust, And Bird Droppings Affect Your Solar Panels
An ongoing accumulation of dust and dirt on the panel surfaces will cause less and less light to reach the PV cells, and over time ( see below), this could snowball into a significant loss of energy.
Bird dropping is one of the biggest enemies of solar panels as not only would they cover the surfaces, but if it got into the microinverters (if you have them), it could cause the units to show a no current flow.
How Much Energy Could You Lose With Dirty Solar Panels?
A few arguments say that dirty solar panels only incur negligible energy losses of around 5% when dirty. Still, over two years, that energy loss could reach as much as 35%!
Over eight quarters without regular cleaning, you would be losing about 5% per quarter, and if you are losing energy, you are losing money! Regular cleaning, in most cases, is about twice a year, but if your area is prone to dust and other debris, you may need to do that every quarter.
What To Use When Cleaning Solar Panels
One of the cardinal rules when cleaning solar panels is don’t use any detergent stronger than dishwashing liquid. This is all you need to get your panels back to that super clean condition as they were when first installed.
More potent chemicals like bleach could easily leave indelible marks on your panels, affecting their efficiency.
Another question is whether you can use a high-pressure washer on your panels, and again, a standard hosepipe or bucket of water is more than enough. High pressure can potentially dislodge components on the system.
All you need is a sponge even for those problematic bird stains and a cloth for the rest and, as an added tip, try and use a long-handled sponge or similar tool to clean your panels as this will make accessing the whole surface more controllable.
When To Wash Your Solar Panels
You might think that you can wash your panels anytime. Get on the roof or ladder with your bucket of detergent and hosepipe, and away you go! But, like most things in this life, nothing is ever that simple.
Remember that solar panels get very hot, so cleaning them during the day’s heat may seem like a good idea, but it’s not. Look to clean your solar panels in the morning before the sun gets high or in the later afternoon after the perihelion is over.
The panels will be cooler, and so will the roof temperature, and this will be a lot more comfortable and safer for you to clean your panels and then allow them to dry.
Hire A Professional Cleaning Service To Wash Solar Panels
Another option may be to spend a little money and hire a company specializing in cleaning solar panels. Many of the installers often have this service available to their customers, or they sub-contract to specialists.
There are good reasons for doing this, including that your panels will get adequately cleaned, and any issues found can be fixed or remedied without delay. Not only that, but professional cleaners will have specially formulated detergents and cleaning equipment to ensure optimum results.
There have also been some innovations produced regarding the cleaning of solar panels. One of those is a dirt and dust resistant coating that prevents accumulation and coagulation of dust and dirt on the panels, and they are washed clean after the rain or with a hosepipe.
Another one that may seem like science-fiction is robotic cleaners that work at night and use a combination of compressed air and soft brushes to clean and polish those surfaces to factory state.