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Can Hail Damage Your Solar Panels?

hail

Hail can damage solar panels by creating both visible damage, and star-shaped micro cracks.

The degree of damage depends on the size of the hailstone, hail duration, the type of your solar panel technology as well as how panels are positioned on the roof.

What is hail and how does it form?

A hailstorm is a form of precipitation that consists of large, often jagged pieces of ice that fall from the sky.

Hailstones can grow to be very big and heavy in size by picking up more water droplets as they move through clouds before falling back down onto the earth.

Hail chunks can be as big as a tennis ball, but more commonly they are the size of a pea.

Most hailstones don’t create large holes in solar panels. Instead, they are more likely to cause small star-shaped cracks which may even be difficult to notice easily.

Hail can be a big problem for solar panels because it has been known to cause damage by puncturing or shattering glass materials that make up your panel. In rare cases, it can also make electric conductors within the panels which makes them inoperable.

But I know you want to hear some number.

According to a study made by Vrije Universiteit Amsterdam in 2019, researchers found that:

On the roof hit by hailstones of 6 cm in diameter, 42% of the modules were showing visible damages. On the other roof hit by hailstones with a diameter of 4 cm, only around 3% of the panels showed visible damages, but 90% star-shaped micro-cracks.

The study not only described the factors that caused hail damage but also pointed the factors that make a solar panel more resilient to hail. Here are those factors you may want to know about:

  • A glass-glass panel instead of a glass-foil panel.
  • Thicker glass (3.2 mm glasses can be destroyed by 5 cm ice balls; 4.0 mm glasses only show micro-cracks).
  • No earlier cracks by transport or snow.
  • Stronger clamps that attach the panel.

According to experiments from Moore & Wilson, hailstorms can have a huge impact on solar panels.

The front layer of the panel is what makes all the difference in determining how much damage will be done by hailstones.

The research showed that utilizing clear silicone potting as the front layer showed that it could not withstand 1 inch simulated hailstones without cell breaking.

Anneal glass, on the other hand, was fit for withstanding up to 1-inch or even 1-1/4 inches of hailstone size. Also, tempered glass can withstand 1-1/2 inch ice balls but breaks when subjected to the force of 2-inch ice balls.

From the research of Moore and Wilson (1978), it was found that tempered glass can withstand hail better than annealed or silicon potting because its surface is less fragile.

Usually, it is difficult to determine what caused micro-cracks in solar panels if they are not visible. Unless special tests can be used that require professional equipment and training, you will need a good guess or hope for the best.

Micro-cracks gradually decrease power output in longer time periods because of heat from radiation which causes them to grow into larger cracks then finally break off completely causing damage as well as weakening the entire panel’s function overall.

Solar Panels’ Positioning Matter

The positioning of solar panels also is a factor that determines the level of hail damage on them.

Average damaged / Total SP (%)Average mean hail size% of claims
Flat18.14.829
Pitched12.64.771
The average number of damaged solar panels out of the total number of solar panels per roof type (based on Achmea (2019) data and PDOK (2016) aerial photos).

Solar Panels’ Orientation

The orientation of the solar panels is another factor to consider. Roofs are classified into eight groups: N, NE, E, SE, S, SW, W, and NW.

However, no claims were found in which the solar panels were oriented N or NE, and only four claims had an E orientation and two had an NW orientation.

Therefore, the below table doesn’t take into account those directions.

The orientation of a solar panel affects the rate of hail damage, even though more or less significant amounts are not always protected.

The SE-oriented panels were found to be more resilient against hailstorms than their counterparts in other orientations and received significantly fewer damages on average.

This could be due to the hailstorm coming from the southwest, making solar panels with the other three orientations less vulnerable.

Solar panels oriented in the southeast have less damage than solar panels in other directions. Except for an S and SE orientation, there is no significant difference between one direction being higher or lower on average when it comes to how much they are damaged.

Solar panels on a roof with S orientation suffer significantly more damage than solar panels with the SE orientation.

Average Damaged /Total SP (%)Average Mean Hail Size% of claims
S17.04.748
SE8.44.918
SW13.64.525
W15.74.99
S, SW, W15.84.781
Average damaged solar panels as a percentage of the total number of solar panels per orientation (based on Achmea (2019) data and PDOK (2016) aerial photos).

Total Number Of Solar Panels

Achmea concludes that roofs with a higher number of solar panels have on average more damage.

This is because the hailstones may bounce off one panel onto another, causing greater injury to both solar panels and their surrounding area (Achmea).

Experts have been seeing an increase in solar panels on roofs, but so far there has not
been a clear trend of increased damage rates.

For example, the average share for small SPs is high at 39.6%, while it hovers around 25% for larger ones with over 100 panels installed per roof.

Average Damaged / Total SP (%)Average Mean
Hail Size
% of claims
1 – 6 SP39.64.64
7 – 15 SP13.65.029
16 – 50 SP10.64.750
50 – 100 SP3.54.36
> 100 SP25.74.611
The average number of damaged solar panels per total number of solar panels (based on Achmea (2019) data and aerial photos from PDOK (2016)).

The above tables may give a first impression of what might influence the damage to solar panels, but it does not link all variables together.

There are still many studies made around the world to create the link between those variables to create a more mathematical approach to the problem.

Is hail damage covered under homeowner’s insurance? 

solar panel hail damaged

The best thing you can do is find out how much coverage your insurance has on this type of event before purchasing new ones.

Most home insurance policies cover hail damage, and if they don’t provide coverage for solar panels as well you may want to update your policy.

How do manufacturers test solar panels for hail resistance?

Solar panel manufacturers put their products through rigorous testing to ensure that they can withstand hail storms.

In most cases, solar panels have been tested and certified to withstand a hail storm with a diameter of 25 mm (one inch) falling at a speed of 23 meters per second or 50 miles per hour.

How can I protect my solar panels from hail damage?

The best way to protect the panels is by monitoring weather forecasts which will indicate if any hailstorms are expected in the region where you live.

Once detected, it’s important that homeowners take necessary precautions like covering their panels with plastic sheeting or tarpaulin coverings.

Bubble wrap or polyethylene foam would also work fine. The idea here is to completely cover solar panels with a material that can absorb the shock.

You’ll need to make sure the cloth covers every square inch of your panel and that it’s firmly attached so high winds don’t tear it loose.