Solar Panels and Colorado Hail

Panels sold for rooftop use are qualified under IEC 61215, which includes a hail test: 25 mm (about 1-inch) ice balls fired at 23 m/s, aimed at 11 specific spots on the module, including corners and edges. To pass, the panel can’t show major visual defects or lose more than a set amount of power.

That’s a meaningful bar. Plenty of Front Range hail is small enough that tempered solar glass shrugs it off. But the test is a floor, not a guarantee. A panel that passes at 25 mm has not been proven against golf-ball or baseball hail. A newer and tougher specification, IEC TS 63397 (published 2022), qualifies modules against larger ice balls. Few spec sheets mention it yet, so ask about it when you compare panels.

Hail season here generally runs from mid-April to mid-September, and the corner where Colorado, Nebraska and Wyoming meet averages about 7–9 hail days a year, according to National Weather Service data. Denver, Boulder, Fort Collins and the plains east of I-25 all sit in that belt.

The storm people still talk about is May 8, 2017. Industry estimates put insured losses from that single Denver-metro storm around $2.3 billion, making it the costliest hailstorm in Colorado history, with roughly 100,000 homeowner claims. Storms like that are rare, but over a 25-year panel life it’s worth planning for one.

The obvious failure is shattered glass. Tempered glass breaks into a spiderweb of small pieces, and the panel usually stays in its frame. A broken panel should be replaced, not taped. Moisture gets in and output drops.

The less obvious failure is microcracking in the cells behind glass that looks fine. It can take months to show up as lost production, which is why the monitoring on your system matters. If output from one panel or string drops after a storm while its neighbors hold steady, that’s your cue to have it inspected.

Tilt matters a little. A panel on a steep roof takes hail at a glancing angle, and a flat-mounted panel takes it more squarely. We don’t pick tilt for hail alone, because orientation matters far more for production, but it’s one reason flush-mounted arrays on low-slope roofs deserve a closer look at panel specs.

Look for the IEC 61215 certification as a given, then ask whether the model has been tested beyond it: to IEC TS 63397 or an independent lab’s large-hail program. Thicker front glass and a stiffer frame generally help, but compare actual test results, not marketing adjectives.

Warranty language is worth reading. Most panel warranties cover manufacturing defects, not weather damage. Hail is an insurance event, not a warranty claim. That’s why the insurance conversation below matters more than the brand name.

Call your homeowners insurer before installation and tell them you’re adding a roof-mounted solar array. Ask three questions. Is the array covered as part of the dwelling? Does adding it change your dwelling coverage limit or premium? How does your hail or wind deductible apply? Some policies carry a separate percentage deductible for wind and hail, and on a hail claim that number decides what you actually pay.

Ground-mounted arrays can be treated differently from roof-mounted ones, sometimes as “other structures” with a lower limit. If you’re putting panels in a field or on a pole mount, get the answer in writing. And if your system is leased or on a PPA, the company that owns the equipment usually insures it. Read that section of the contract.

On the Front Range, hail replaces roofs more often than it replaces panels. If your shingles have 8–10 years left and your panels will last 25 or more, you’re setting up a second project: pulling the array off, reroofing and putting it back. We don’t do remove-and-reinstall, so we’ll tell you plainly when a roof should go first, or be done together with the solar. We do roofing, and one crew handling both avoids two warranties pointing at each other.

If a hail claim is already replacing your roof, that’s often the cheapest moment to add solar, because the tear-off is already paid for. Ask your adjuster about impact-rated (UL 2218 Class 4) shingles while you’re at it. Colorado is also setting up a resilient-roof grant program under SB26-155, signed in June 2026 and funded by an insurer fee starting in 2027. How homeowners will apply hasn’t been published yet, so check its status before you plan around it.

Don’t climb on the roof. Walk the yard for glass fragments, look at the array from the ground with binoculars, and check your monitoring app for any panel or string that fell behind its neighbors on the next sunny day. Photograph everything with dates before cleanup.

If we installed your system, call us and we’ll inspect it and document damage for your adjuster. If another company installed it, contact them or the equipment warranty provider first. We don’t service or take over other installers’ systems.