After only a few months with a rooftop solar system, one homeowner said pollen and bird droppings were quickly collecting on the panels. The buildup appeared to affect the system's performance too, with output dipping during the brightest stretch of the day.

Here's what to know

The homeowner then turned to Reddit's r/SolarDIY community to ask whether spraying the panels off at midday would help restore production, or whether the sudden temperature change would damage the glass.

The homeowner posted the question in the Reddit thread: "Wondering if I need to worry about thermal shock if I hose my panels down on a hot day." 

They also said that grime on the panels was already causing a visible "production dropoff" when the sun was most intense.

Replies didn't fully agree on the level of risk, but much of the practical guidance pointed in the same direction. While some people advised against rinsing panels while they are hottest, others said tempered solar glass is built to handle outdoor temperature swings and compared hosing panels down to rain hitting them on a hot day.

One commenter asked, "Why not [wash them] in the morning before they heat up?" Another wrote, "Make sure you can touch their metal frames barehanded without discomfort, and that your cleaning water isn't icy cold. Early AM and after-sunset are the recommended times." 

A third user said, "Never had a problem cleaning panels in the middle of the day with people's tap water. Makes it easy when they are warm to get the grime off. I get the logic… But if this were the case, panels would be breaking all the time in Florida rain."

More background

Commenters also stressed that cleaning panels takes more care than many household chores. The discussion touched on timing, water temperature, and method, and one commenter specifically said to avoid pressure washing, use a soft cloth, and use cleaning products cautiously.

Waiting until early morning or evening may not be convenient, but it can help reduce risk and protect the equipment.

For homeowners still interested in going solar, EnergySage's free services can also clarify the bigger financial picture. Homeowners considering panels can explore EnergySage to get free solar installation estimates and compare quotes. Those who do can save up to $10,000 on installations.

Where can I learn more?

These stories also show how routine upkeep connects to the bigger math of owning solar at home.

• Some solar owners found a simple rinse can unlock roughly 5% more power.

• One homeowner found a simple cleaning hack dramatically boosted panel performance.

• At EnergySage, Charlie Hadlow helped unravel the mystery of solar panel costs.

If you're dealing with pollen, dust, or droppings on your panels, these articles can help you sort out what cleaning can solve and what depends on the rest of the setup.

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