If you already have solar panels on your property or are planning to install them in the near future, then you’ll be concerned if they can be damaged by hailstones. As solar panels are a large expense and hail is a natural phenomenon – Engineering Passion wants to ensure you understand how a hailstorm can affect your solar panel system.
In this article we’ll be covering how solar panels have been designed and tested to withstand damage from hail, what hailstorm conditions could result in solar panel damage and what you can and should do to protect them, so they can last for decades or even longer.
First, let’s dive into some background information on hail.
What is hail?
Hail is formed when moisture in clouds freezes into ice particles that get blown around in strong winds. Most hailstones measure approximately 0.2″ (~5 mm) but can span up to 5.9″ (15 cm) in diameter and can be round or jagged .
A recent report on the effects of climate change on hailstorms has suggested that hailstorm frequency may decrease in East Asia and North America but is expected to increase across Australia and Europe. But interestingly the report also indicated that in most regions, hailstorm severity is expected to increase with climate change .
In the most severe conditions hail has the ability to damage airplanes, homes, and cars. Hail can also be deadly to people and animals if unprotected.
Unsurprisingly, solar panels are susceptible to being hit by hailstones. As they are usually positioned on top of your home or business, so solar manufacturers have designed solar panels to be weatherproof.
How are solar panels designed and tested to withstand hail?
Solar panels are designed to be durable and rigorously tested in order to withstand hail. They are constructed to endure the various weather conditions while also exceeding testing requirements ensuring that they deliver the maximum power output.
In fact, solar manufacturers have a test called “Solar Hail Impact” or “Solar Hail Test”. This test assesses the effect of hail on solar panels using advanced testing machines.
How is the ‘solar hail impact’ test performed?
The solar panel under test is first mounted on a vertical shaft, within close proximity to the machine. The machine then fires hailstones towards the panel at different angles and speeds. This test ensures that solar panels withstand hail damage.
You can watch this video from SolarWorld to see this test in action:
What are solar panels made of?
Solar panels are made of semiconductor materials. They use solar energy to generate clean electricity. The generated solar power can be stored using a battery for later use. The most common semiconductor material of a solar PV panel can be either crystalline silicon or amorphous silicon (thin-film PV panels).
Read Related Article: What is a solar panel and how does it work? (Ultimate 101 Guide)
Crystalline Silicon Solar Panels
A collection of small silicon cells makes a crystalline silicon PV module. It’s then mounted to a frame (usually made of aluminum) and covered with layers of tempered glass and encapsulant.
Crystalline silicon panels are commonly used in homes because of their high efficiency. In the crystalline silicon category, you will find monocrystalline and polycrystalline solar panels.
Thin-film Solar Panels
Thin-film solar panels are made of amorphous silicon and are generally coated with a layer of plastic. They are becoming more popular because they are cheaper to make and easier to install.
Thin-film cells are considerably lighter and more flexible than glass-coated solar cells. Since they don’t have to support the weight of an entire window. But, in terms of efficiency thin-film panels are less efficient than crystalline silicon panels.
Solar Panel Glass Protection
While it’s essential to think about panels that are efficient and powerful, you shouldn’t overlook the fact that solar panels are a long-term investment with a lifespan of decades.
The glass barriers provide protection from external damage such as hail, rain, and dust. Thus, it’s critical to pay attention to the sort of glass protection they have in order to make sure they are both durable and safe.
When it comes to solar module glass, you basically have two options:
#1 Tempered Glass
Tempered glass also known as toughened or safety glass – is four to six times stronger than a normal glass (plate glass) of the same thickness. The tempered glass for solar panels is made by either thermal or chemical methods.
When toughened glass is damaged, it shatters into many small pieces but stays relatively together, rather than splitting into thousands of pieces of sharp splintered glass. By shattering into tiny pieces, it reduces the danger of a serious injury.
#2 Plate Glass
Plate glass or flat plate glass on the other hand is more fragile. It will typically crack during a storm which can actually compromise its effectiveness. Plate glass is manufactured by slowly pouring molten glass onto a flat table where it cools and solidifies.
Solar Panel Glass – Tempered VS. Plate
While plate glass can be strong, hail can shatter the relatively fragile material. Whereas tempered glass will often withstand significant impact without damage. Tempered glass has a high safety rating as compared with plate glass.
High-quality crystalline solar panels from reputable manufacturers utilize tempered glass. They have 3 to 5 mm thick tempered glass which can withstand most hailstorms.
Most thin-film solar panels, on the other hand, can only use flat plate glass due to their method of construction. Some producers use thicker flat plate glass to compensate for this comparative disadvantage. However, this is still not as strong as utilizing white tempered glass.
Thus when buying a solar panel, make sure that the solar panel’s datasheet clearly states that the panel utilizes thick tempered or toughened glass which is measured in millimeters (mm) and should be approx. 3 mm or more.
Can hail damage solar panels?
Hail and Light Hailstorms
The good news is that small hail or a light hailstorm will not damage solar panels, due to the protection of the tempered glass or toughened glass. A solar module from reputable manufacturers with tempered glass can resist wind impacting up to 125mph which equates to hailstones the size of a softball .
Large Hail and Severe Hailstorms
Although most solar panels are made of tempered glass that is less prone to cracking than ordinary window glass, under the impact, they’re still vulnerable if struck by a large enough hailstone traveling with significant speed.
Reports show that the most destructive storms are the ones that have large hailstones, especially those with diameters of 1.5 inches (∼38 mm) or more.
The problem with large hailstones is not so much their weight. But rather the speed at which they impact a surface after being carried by high-speed winds through updrafts in thunderstorms. Speed is key because it takes energy to cause damage. The greater the energy, the more likely the solar panels will be damaged.
Large hail can cause the toughened solar panel glass to shatter or can cause dents in the panel. It can also induce microscopic fractures in the silicon photovoltaic cells.
If the toughened glass layer is compromised then it’s likely that water will find its way into the solar module. Moisture within the panel may cause a decrease in energy output, a cell short-circuit , or even irreparable damage, potentially destroying the panel.
As a word of caution, it’s wise not to touch a broken solar panel or solar array since contact might result in a short circuit. Always contact your local experts or technicians for help or repair when you notice apparent solar panel hail damage.
What are some ways to protect your solar panel from hail?
As explained above, when hail damages a solar panel, it can cause physical damage. Thus reducing a panel’s performance or rendering it destroyed and unusable. Fortunately, there are several things you can do to protect your solar array from hail damage.
#1 Solar Panel Protective Covers
One of the best ways to protect your solar array from hail is by using protective covers. Protective covers are made out of high-quality materials. They can deflect hail, and protect the panel underneath it. With a protective cover equipped on your solar panel, there’s no need for an actual hail guard or shield because the cover itself is enough protection.
However, when looking for a solar panel protective cover, be selective since not all of them are designed to protect your panels from hailstones. The disadvantage of using a protective cover is that it will reduce power generation since it will also obstruct sunlight. However, if you only use the cover during particularly extreme weather conditions, there is no problem.
#2 Use a Layer of Methacrylate Coating
Methacrylate coating is another effective way to protect your solar panels from hailstones. The reason why this method works is that methacrylate acts as a hail guard for the solar panel underneath it. When hailstones hit the coating, the solar panel has more strength to repel impacts to it. As the methacrylic coating is quite thin, light easily passes through it.
#3 Tilt the Solar Panels at an Angle
If you live in a hail-prone region, one of the most cost-effective methods to protect your solar panels from hailstones is to install them on an adjustable frame that can be tilted to a vertical position depending on the weather forecast.
It’s more advisable to stay inside during a hailstorm than to go out and shield your solar panels from hail. If you’re overly concerned about your solar modules, you may set up a weather alert on your phone ahead of time so that you can adjust them before a storm approaches. There are also frames that can automatically adjust. But these come at a higher cost.
Do solar panel warranties cover hail damage?
Before we get into the specifics of this question, let’s take a look at the sorts of warranties offered by solar firms.
Solar panel companies generally give two distinct sorts of warranties on their panels:
#1 Energy Production Solar Panel Warranty
The energy production warranty ensures that your solar panels will maintain at least 80% output capacity for the duration of their 25-year warranty. Simply said, the panel’s output is guaranteed to be 80% of its rated output at year 25.
#2 Product/workmanship Solar Panel Warranty
The second warranty for solar panels is the product/workmanship warranty. The product/workmanship warranty ensures that your panels are free from defects in materials and workmanship, such as discoloration or delamination. This warranty ensures that your solar PV system will last 25 years at a minimum.
The majority of solar product warranties cover the basic function of typical solar equipment, such as panels, inverters, and batteries. Additional protection against extreme weather, such as hailstones or tornado damage, may be included in your solar warranty but most manufacturers don’t provide them.
Solar panel companies that provide a solar hail damage warranty ensure protection against one-inch hailstorms at 50 mph . To maintain the integrity of this warranty, always contact your solar panel’s provider in case an issue happens to your solar panels.
Solar Panel Warranty of Popular Brands
|Brand||Standard Length||Annual Power Declining (%)||Power Output (%)|
|Panasonic Solar Panels||25 years||0.26%||>93.5% over 25 years|
|SunPower||25 years||0.3%||>92% over 25 years|
|LG Solar Panels||25 years||0.4%||>90.02% over 25 years|
|Tesla Solar Panels||25 years||0.5%||>87.5% over 25 years|
|Canadian Solar||25 years||0.7%||>80% over 25 years|
Does homeowners insurance cover hail damage to solar panels?
If you’re considering solar panels for your home, this is a question that’s probably on your mind. The simple answer? Yes, and maybe. Solar panels are typically covered from storm damage by household insurance or roof repair policies available from general or specialist insurers.
And if you live in the United States, Europe, Canada, the United Kingdom, or Australia, and if normal hail is typical there, your insurance policy may include hail damage as part of your house coverage. However, if your location is vulnerable to severe hail conditions, you should double-check that your policy does not contain exclusions for solar PV panels damage caused by devastating or massive hailstorms.
How To Detect Hail Damage to your Solar Panels?
#1 Visual Inspection
The first thing to do is merely look at your solar PV panels. Sometimes, it’s just as simple as that and the storm damage should be obvious and easy to correct. If your solar array appears to have small dents in them, broken glass, dark spots – any evidence that could indicate an impact on the integrity of the solar cells – it is a good idea to contact a solar panel installer or contractor to inspect your panels for hail damage and provide options for repair if necessary.
Don’t try to repair them yourself, because this may result in deadly electric shock, as well as void the solar panel’s warranty.
#2 Measure Performance of Your Energy System
The next step is to check the solar power output curve of your solar energy system. Your solar energy monitoring system or mobile app can determine how much power in kilowatts you’re currently generating in real-time.
A decrease in the amount of solar power being produced can mean that there’s increased resistance or that there are more serious issues such as a broken solar panel. You should contact a specialist or contractor to inspect and fix these problems for you.
Frequently Asked Questions
What size of hail can damage a solar panel?
Although most solar PV panels are made of tempered glass that is less prone to cracking than ordinary window glass under the impact, they’re still vulnerable to damage if struck by a large enough hailstorm stone.
The majority of hail damage to solar panels is caused by hailstones that are bigger than an inch (∼25 mm) in diameter. Large-sized hail, especially those with diameters of 1.5 inches (∼38 mm) or more, are generally the source of evident storm damage.
What is the Tesla Solar Roof Hail Test and How Durable Are They?
Like any other solar panel manufacturers, Tesla also tests their solar panels against hail damage. Solar panels are put to the test against one-inch hail, which is considered a severe form of hailstorm in many areas.
But according to Tesla, the Solar Roof tile can withstand hail as large as 1.75 inches and up to 166 mph winds.
These wind and hail ratings along with their warranty of 25 years make Tesla Solar Roof a little more durable than traditional solar panels.
In conclusion, hail damage should not be a major issue with a modern solar PV system. Solar panels are designed to withstand hails and are well tested in labs before they are shipped.
However, if the hail is larger than an inch in diameter, your solar panels are likely to be damaged in the most severe hailstorms. So, if you’re living in an area where hailstorms are happening occasionally and your insurance company doesn’t cover it by default, then you can consider adding protection against hailstorms to your insurance policy. This will give you peace of mind.
If you do experience hail damage, make sure to get in touch with your solar installer right away. They can work with you and insurance companies if necessary to get the system repaired.
Other than hail, solar panels can also be harmed by harsh wind, heavy snowfall, or flying debris during a powerful storm.
As a final note, if you want to use a solar panel protective cover, be sure it’s only for short periods of time since this can reduce power production.
 Hail Formation
 A report on the effects of climate change on hailstorms.
 A solar module can resist wind impacting up to 125mph.
 Moisture buildup within the panel.
 Solar panel hail damage warranty ensures protection against one-inch hailstorms at 50 mph.
 Tesla Solar Roof tile can withstand hail as large as 1.75 inches and up to 166 mph winds.