Can Cleaning Hot Solar Panels With Water Crack Them?
Yes, pouring much cooler water onto very hot solar panels can create thermal stress and potentially crack the glass. That is why solar panels are generally best cleaned when they are cooler, such as earlier in the morning.
This does not mean spraying water on a solar panel automatically breaks it. The concern is a large and sudden temperature difference between the panel and the water.
What Is Thermal Shock?
Solar panels sitting in direct Arizona sun can become much hotter than the surrounding air.
If much cooler water suddenly hits hot glass, parts of the panel can cool and contract faster than others. That rapid temperature change is called thermal shock.
REC specifically recommends cleaning panels while they are cool to avoid breakage from thermal shock.
LONGi provides an even more specific guideline. Its maintenance manual says the temperature difference between the cleaning water and the solar module should not exceed 10°C, or 18°F.
Will Normal Hose Water Crack Solar Panels?
Usually, normal hose water is not automatically a problem. The temperature of the panels and water matters.
At Cheetah, our filtration system connects to the homeowner's outdoor water spigot. The water then passes through our purification system before reaching the solar panels.
In Arizona, the water sitting inside an outdoor hose can actually be quite warm when it first comes out.
However, that does not mean thermal shock can be ignored. Once the standing water clears the hose, the incoming water may be considerably cooler than a panel that has been heating in direct sunlight for hours.
That is why the better approach is to avoid cleaning extremely hot panels rather than relying on the hose water being warm.
What Is the Best Time to Clean Solar Panels?
Earlier in the day is generally better.
Canadian Solar recommends avoiding the hottest hours of the day specifically to reduce thermal stress. Its customer guidance recommends early morning or late evening when possible.
For Arizona homes, this becomes especially important during the hottest parts of the year.
Does Cheetah Use Cold Water?
We do not bring a tank of ice cold water and spray it onto hot panels.
Cheetah connects to the home's water supply and runs that water through our purification system. We use purified or deionized water with a non abrasive brush to clean the panel surface.
Purified water also helps reduce the mineral residue that ordinary hard water can leave behind.
Learn more about our solar panel cleaning service.
Can You Clean Solar Panels in the Afternoon?
It may be possible depending on the conditions, but the hottest part of a sunny Arizona afternoon is not the ideal time to suddenly cool extremely hot panels.
The safer approach is to consider:
Panel temperature
Water temperature
Direct sunlight
Time of day
Manufacturer cleaning instructions
Different solar manufacturers can have different maintenance requirements, so the manufacturer's instructions for your specific panels should take priority.
What Else Can Damage Solar Panels During Cleaning?
Temperature is only one concern.
Improper cleaning can also involve:
Abrasive brushes
Scraping dry dirt from the glass
Excessive pressure
Standing or kneeling on panels
Harsh chemicals
Pressure washing
Cheetah uses purified water and a non abrasive brush on the solar panel surface rather than harsh cleaning chemicals.
The Bottom Line
Yes, a large temperature difference between very hot solar panels and cooler cleaning water can create thermal stress.
That does not mean normal professional solar panel cleaning is likely to crack your panels. It means the cleaner should pay attention to temperature, avoid unnecessarily cleaning extremely hot panels, and follow appropriate cleaning practices.
If your panels need cleaning, learn more about professional solar panel cleaning in Arizona or call Cheetah Solar Panel Cleaning and Pigeon Control at (623) 300-1924.
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