Image: @RACQOfficial
While all solar panels installed on homes in Australia have basic hail resistance characteristics, some manufacturers go a step further to provide additional safety and a competitive advantage. But we are seeing some hailstorms here that no panel can survive.
What standard level of hail resistance do solar panels have?
Hailstorm testing is mandatory under both Australian and international photovoltaic (PV) standards. For crystalline modules and thin film modules, IEC 61215 requires that modules must withstand impacts from ice balls with a diameter of 25 mm and a speed of 23 m/s (82.8 km/h) at 11 locations in the module in a moderate test (Class MH); or 75mm diameter for the hard test (Class SH).
More stringent, advanced tests include the Swiss Hail VKF-HW4 standard used by organizations such as Germany’s TÜV Rheinland.
The glass factor
The most important hail protection of a solar module is the front cover glass. This is “tempered” glass created by heating regular glass and then rapidly cooling it, making it four to five times stronger than regular glass.
The glass also contributes significantly to the weight of a panel. Older solar modules usually have a 3.2 mm thick cover glass. But over the years, some manufacturers have reduced the thickness of the front glass. It could be as little as 1.6mm; However, this is usually the case for modules with double glass (front and back) and bifacial modules. with the rear glass providing additional stability.
Which panel manufacturers offer improved hail impact resistance?
The following list is not intended to be exhaustive, but shows some example models of residential roofs from various manufacturers that are currently listed in the SolarQuotes Recommended Solar Panel Brands Chart with Improved Hail Resistance.
| Manufacturer | Example model | hailstone size | speed | standard |
|---|---|---|---|---|
| Aiko | Everything current | 40mm | 100km/h | Swiss VKF HW4 |
| Canadian Solar | CS6.2-48TD | 35mm | 83 km/h | IEC 61215 |
| Maxeon (solar power) | Everything current | 45mm | 108 km/h | Swiss VKF HW4 |
| Phono Solar | Diamond double lens | 45mm | 110 km/h | IEC 61215 |
| Suntech | Everything current | 45mm | 110 km/h | VDE – inspired by the Swiss standard |
| REC | Alpha Pure RX | 45mm | 110 km/h | IEC 61215:2021 |
| Winaic | Everything current | 35mm | 100km/h | Swiss VKF HW4 |
As for the difference in kinetic energy per impact, according to REC, the ability to withstand 45mm at 110km/h represents ten times more per impact than the industry baseline of 25mm at 82.8km/h.
If hail resistance is important to you, be sure to read a solar panel’s data sheet carefully as there may be differences between models of the same brand.
Hidden damage – micro cracks
Note that testing does not assess the possibility of cell damage beneath the glass, even if the glass is not broken – for example, microcracks.
Microcracks are tiny, sometimes invisible breaks in cells caused by stress. Over time, microcracks can grow, resulting in power outages, the formation of hotspots, degradation of panel performance, and potentially safety issues such as moisture intrusion.
Microcracks in solar panels are best detected using electroluminescence (EL) imaging, which highlights these and other defects as dark areas.
EL imaging shows damage caused by microcracks (dark areas). Source: Winaico.
When are the hailstorm “seasons” in Australia?
Under the appropriate atmospheric conditions, severe hailstorms can occur at any time of the year. But general seasonal trends in each Australian state and territory are:
- New South Wales & ACT: September to February. Peak activity generally occurs in November and December.
- Victoria: Spring and Summer (September to March).
- Queensland: Spring and summer months. Southeast Queensland is considered a supercell hail hotspot.
- South Australia: Occurs mainly between October and February.
- Western Australia: Varies by region. Perth: more common from May to October. In the northwest from November to April.
- Tasmania: Not as common as on the mainland, but more associated with storms associated with cooler months.
- Northern Territory: During the rainy season, which lasts approximately November to April.
A wild card in all of this is climate change. According to a UNSW study published in July this year, climate change could cause hailstorms to become more frequent and damaging in some Australian cities; including Sydney, Canberra, Melbourne and Perth.
There is hail, and then there is hail
A 25mm hailstone can penetrate a lot, 45mm hailstones are quite large (about the diameter of a golf ball) and 75mm hailstones are huge. But the hailstones seen in a 2020 storm in Queensland were monstrous – up to *140mm*. Forget the panels, imagine one of them hitting your head.
The Insurance Council of Australia (ICA) declared the damage caused by the 2020 storm, which resulted in thousands of vehicle and property damages, a catastrophe.
Check your home and contents insurance for hail protection
Regardless of the hail protection rating of a solar panel, we have seen some storms in Australia produce rocks that no panel can survive unscathed unless you are lucky.
In this case, make sure you have told your homeowners insurance company that you have a solar power system and confirm that hail damage is covered. In a worst-case scenario, this call could save you a lot of money.
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