This article is based on analysis published by SolarQuotes
Australian rooftop solar systems are built to withstand a reasonable level of hail impact. All panels installed locally must meet mandatory testing standards designed to cope with common storm conditions. But as extreme weather events become more frequent and severe, some manufacturers are going beyond the baseline to offer enhanced hail resistance to provide peace of mind for homeowners and installers.
What standards require
Hail impact testing is compulsory under both Australian and international photovoltaic (PV) standards. For crystalline and thin-film modules, IEC 61215 requires panels to withstand impacts from ice balls measuring 25 millimetres (mm) in diameter, fired at 23 metres per second (82.8 km/h) at multiple points across the module. This is known as the moderate hail (Class MH) test.
A more severe optional test, Class SH, uses 75 mm hailstones, representing extreme conditions rarely seen but not impossible in parts of Australia.
Some manufacturers also submit their modules to more stringent independent standards, such as the Swiss VKF HW4 test, administered by organisations including TÜV Rheinland. These tests simulate larger hailstones at higher velocities, pushing well beyond International Electrotechnical Commission (IEC) minimums.
Why glass matters
A solar panel’s primary defence against hail is its front cover glass. This is tempered glass that is heated and rapidly cooled, making it around four to five times stronger than standard glass.
Traditionally, most panels used 3.2 mm thick front glass. In recent years, some manufacturers have reduced glass thickness to cut weight and cost, sometimes down to 1.6 mm. Thinner glass is typically paired with dual-glass or bifacial designs, where the rear glass adds structural strength.
And so, it is important for installers to remember that not all panels are built the same, even within the same brand family.
Which panels offer enhanced hail resistance
A number of residential-grade panels available in Australia exceed baseline hail standards. According to SolarQuotes, examples include models rated to withstand 35-45 mm hailstones at speeds of up to 110 km/h, depending on the manufacturer and test standard used.
Renewable Energy Certificates (RECs) note that panels rated for 45 mm hail at 110 km/h absorb around ten times more kinetic energy per impact than the IEC baseline requirement.
Installers are advised to always check the datasheet as hail ratings can vary significantly between models, even under the same brand.
Microcracks
One limitation of hail testing is that it focuses on whether the glass breaks. It does not assess what happens beneath the surface.
Even when the glass remains intact, hail impacts can cause microcracks in the solar cells – tiny fractures that may be invisible to the naked eye. Over time, these cracks can grow, leading to reduced output, hotspots, accelerated degradation and, in some cases, moisture ingress.
Microcracks are typically identified using electroluminescence (EL) imaging, which highlights damaged areas as dark regions across the cells.
When do hailstorms occur in Australia?
Hail can occur year-round, but seasonal patterns differ by region:
- New South Wales and Australian Capital Territory: September to February (peak in November-December)
- Victoria: Spring and summer
- Queensland: Spring and summer, with south-east Queensland a recognised supercell hotspot
- South Australia: October to February
- Western Australia: May-October around Perth; November-April in the north-west
- Tasmania: Less frequent, more common in cooler months
- Northern Territory: Wet season (November-April)
Climate change is adding further uncertainty. A July study from University of New South Wales suggests hailstorms could become more frequent and more damaging in various cities across the country; including, Sydney, Canberra, Melbourne and Perth.
When hail exceeds all ratings
While 25 mm hail is manageable and 45 mm hail is severe, Australia has already seen events far beyond any test standard. During Queensland’s 2020 supercell storms, hailstones reportedly reached up to 140 mm in diameter.
The resulting damage prompted a catastrophe declaration from the Insurance Council of Australia, with thousands of vehicle and property claims lodged.
At that scale, no rooftop solar panel can realistically be expected to survive.
Insurance still matters
Regardless of a panel’s hail rating, extreme weather remains unpredictable. To mitigate this, installers can encourage customers to notify their insurer when a solar system is installed and confirm that hail damage is covered under home and contents policies.