Solar modules are certified to withstand hail – not Texas-sized hail balls, but your typical hailstones. One quality solar panel manufacturer put it this way: “The panels are tested by shooting balls of ice at terminal velocity at the module in 11 specific spots. The ice balls can be of different sizes and the firing velocities change based on size. Typically solar panels are tested using 25mm balls fired at 23 m/sec. However, the spec also defines larger and smaller ball sizes from 12.5mm fired at 16 m/sec to 75mm fired at 39.5 m/sec. I have yet to see a panel with tempered glass fail using any size ball/velocity. I have seen a few cases of the roof being damaged beyond repair by hail and the unbroken solar panels need to be removed so the roof can be replaced. In short, we test our solar panels extensively for hail survivability. They pass quite well. However – all panels must pass this testing or they could not be certified to put on the roofs of houses, so this may not be a unique selling point.”
In other words, it is a common question, but usually a non-issue. Hail that will break car windshields is hail that will break solar panels. How often do we see such hail? Hardly ever.
