Solar panels are designed to be used outside in all types of weather.
This means that they are highly waterproof and can withstand heavy rain and cleaning with liquid.
If you have traditional rigid solar panels on your house then you can expect them to be waterproof.
In fact, solar panels are so well built that you will still see electricity being produced when it is raining!
Let’s take a closer look at solar panel waterproofing, problems to watch out for, and what types of solar panels are not waterproof.
For the first half of this article, we will be talking about traditional rigid aluminum frame solar panels you find on buildings. For information, on portable and flexible solar panels head further down the page.
What Makes a Solar Panel Waterproof?
Solar panels are inherently waterproof thanks to the design and materials used to build them.
Of course, this is no accident.
Solar panels are designed to be highly durable for use outdoors. This means they can easily keep water out and should last for decades!
Inside are silicone solar cells and wiring which need to be kept dry. If water got inside it would damage the cells and lead to short-circuiting. Just like any other electronic circuit.
To create a waterproof seal, these interior components are sandwiched between reinforced tempered glass and thick plastic, known as a polymer sheet. Then an anti-rust aluminum frame runs around the edges of the panel with waterproof sealant at every joint. This tough design keeps water out.
The only other part of a solar panel is the insulated exterior wiring which runs from a waterproof junction box. This stops any rainwater from getting to the circuit via the cables.
Solar Panel Waterproof Testing
Solar panel manufacturers and installers must ensure the equipment is fit for purpose. This means meeting durability, performance, and safety standards set out by bodies like the National Renewable Energy Laboratory (NERL). Adding to this, they must adhere to local residential building codes which have extensive requirements when it comes to electricity supply.
To pass these tests and requirements the solar panel must be completely waterproof. Along with this, it must stand up to all adverse weather including wind, rain, snow, and hail.
These building codes extend beyond the solar panel itself to the installation. For example, the solar panel installed on a roof must meet the building waterproofing code requirements. An installer can’t simply drill a hole in your roof and put a screw in, they must ensure it is still watertight.
Solar Panel Warranties and Insurance Against Water Damage
There are two other ways you are protected against water damage to your solar panels – warranty and insurance.
Most solar panels have a very long warranty. This warranty will generally have 5 or 10 year materials and labor to cover you for any faulty materials or workmanship. Then you will also find huge 25 year power output warranties. This means the manufacturer guarantees a minimum level of power over that time span. Usually, this is something like 10 years at 90% and 25 years at 80% power output.
Adding to this you should also make sure your home insurance covers your solar panels in case of damage. Just like if you sustain any other damage to your property you will be covered for repairs or replacement. In the event that you sustain water damage from storms or flooding, you won’t be left empty-handed.
Now you can see that all home solar panels are waterproof, let’s look at the other types of solar panels.
Are Portable Solar Panels Waterproof?
Portable solar panels are not always waterproof. In fact, they are more likely to be water-resistant.
This is an important distinction as water resistance means it can take a light splash or misting of water. But it will not be completely watertight. That means water would eventually get inside your panel if exposed for too long.
You should avoid leaving portable solar panels in the rain or near water unless you are 100% it is waterproof.
It also means that they are not fit to permanently mount on building or vehicle rooftops.
Due to the wide range of designs, every portable solar panel is different. You should check the waterproof rating in the technical specification before making any decisions.
Are Flexible Solar Panels Waterproof?
Yes, flexible solar panels are very waterproof which makes them very popular on vehicles like boats, campervans, and busses.
The flexible solar cells are wrapped in ETFE plastic which makes them very durable and completely watertight.
Flexible solar panels will not have any problems being left in the rain or splashed with water on the deck of a boat.
While they have strong durability, flexible solar panels will never be as long lasting as traditional rigid solar panels. However, the big benefit is that they offer a much lighter and slimmer panel which is can be mounted on uneven surfaces or sewn into fabrics.
Do Solar Panels Work in the Rain?
Yes, a solar panel will still work in the rain.
If you check the electrical output of a solar panel in the rain your will still see a current flowing. This is because sunlight can still pass through the rain clouds to hit the solar cells on your panel.
Unfortunately, your solar panel will be much less efficient in the rain, and electricity creation will drop significantly. This is because far less sunlight passes through a cloud, plus water droplets will block light even more.
Final Words on Waterproof Solar Panels
Solar panels are completely waterproof.
They have to be, otherwise they would be unfit for purpose.
Your equipment is designed to be permanently installed outside and last for decades, sometimes over 40 years.
This means that it is resistant to all weather including rain, snow, hail, and ice.
In fact, rain can be very beneficial to the maintenance as it helps to clear away dirt and dust. In addition, you can happily wash your solar panels with water when they get dirty, just like cleaning a window!
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.