Cleaning solar panels: why, when and how you should do it
We like to keep our windows clean so why should solar panel cleaning be an exception? The problem is when do you need to offer a bit of solar panel care and how? Solar panel maintenance is a question that baffles many panel owners.
To help clear up some of the confusion, this Energy Matters article examines how to clean solar panels without injuring yourself or damaging the panels in the process.
We look at solar panel requirements: what you clean them with and how. We also look at the primary sources of dirt, and when you need to call in the professionals.
Dust, leaves and water – common solar blockers.
Can dust cause regular problems or just the build-up of grime over the years? It all depends on where you live for a start and what is causing it.
A bit of dust may have little effect, according to tests done by Ontario Solar Installers, because light can still get through. They recommend that you let nature take its course and the rain will accomplish most of the task of solar panel cleaning.
A test done by one solar company found the amount the efficiency is lowered is minute – maybe 5 per cent or less. And, with a typical 5 kW solar system, this might equate to about $20 of loss in your energy bill. Another solar company found that a thorough clean made the panels 3.5 per cent more efficient.
Leaves also block light. In an experiment carried out by company Mountain View, cleaning flat panels “doubled their energy overnight” after 15 months of operation. However, the tests confirmed that rain on rooftop panels also tends to do the job.
Particular attention should be given to PV arrays situated in dustier areas if they are near farmland or next to a main road. These panels have far more dust and dirt to contend with and will require a more frequent clean.
Bird droppings: Solar Enemy No. 1
Bird droppings on your panels are more detrimental than a film of dust. Do your solar panels have a string inverter or micro-inverters? This is important because systems with micro-inverters, with an inverter attached to each separate panel, can show where one panel has been covered with droppings because that inverter will stop showing current flow.
If you have a lot of trees nearby, especially deciduous ones, they will not only drop leaves on your panels. They will also attract birds.
One thing to consider is the angle of your panels. Flat solar panels will need more cleaning as water can pool up and leave a muddy residue when it evaporates. Angled panels take advantage of rain running across them to keep them clean.
Solar panel cleaning: Is it worth getting professionals?
Calling the professionals may not be worth it for a bit of dust building up over time. But doing it yourself could be costly and undoubtedly dangerous if you fall off the roof.
One idea would be to upgrade your system, so you make increased savings that way. But if you play it safe, there are other advantages of cleaning. You can see if cricket balls or debris from storms have cracked the panels. Also, check for wasps, possums and even bird nests.
How do I go about cleaning solar panels?
What is the best way to clean solar panels? For the DIY-minded you should find the materials at home. Because you don’t want to scratch the panels in any way, it’s best to use just water and a non-abrasive sponge to apply soapy water.
Use a standard hose, don’t use anything high pressure, you might do some damage. Use a sponge if the birds have made a mess and nothing stronger than the detergent you would use with your dishes. You don’t want any strong chemicals marking the solar panels.
Solar power maintenance, safety first!
The best way to clean the panels is from the ground, with a long-handled implement. But if that’s not possible and you choose to go on the roof, you must take precautions.
No one should be on a roof without a hard hat and a safety harness. It is a potentially fatal environment. Check out this advice about working on roofs before you start. The task of solar panel cleaning is not worth your life!
Solar panel cleaning: Conclusion
The average bit of dust will be washed away by the rain, and it won’t be worth getting the professional cleaners. If you are in a heavily polluted area, or there could be some extra dirt or obscuring objects up there, break out the garden hose and clean the panels down, keeping your feet on the ground.
If something is not budging or you need to clean a whole lot of grime and bird poop off the panels, then follow the safety precautions and get up there when it’s a cold day, and you have a safety harness and hard hat.
Use a sponge with washing-up liquid to clean the panels gently. Ultimately, you may decide to leave the cleaning to the professionals and make spot checks to see how badly they need cleaning.
One solution to prevent you having to climb up on a ladder to inspect the panels could be to have a professional company install a CCTV camera pointed at the panels so you can see for yourself when they need cleaning.