A blizzard hits and covers the sidewalks, your yard, and your solar panels in a heavy blanket of snow. You start shoveling your driveway and begin to wonder about your solar array. Do you need to be worried about the health of the solar panels? Will you see an increase in your electric bill?
Not to worry. As long as your system has been professionally installed, your array is built to handle some of the worst that Mother Nature can throw at it.
First things first.
Snow on solar panels will affect the array's production
But don’t let that scare you! When a solar panel is covered by a thick layer of snow, it’s blocked from sunlight and can’t generate energy. However, in the larger picture of your energy savings, snow has an insignificant effect on your solar production.
You don’t need to worry about less energy generation during the winter
Winter days are significantly less important than summer days when considering overall energy generation.
During the summer, solar produces more electricity than your property uses during daylight hours. The excess electricity is sent back to the utility grid. You can be compensated for the excess electricity via net metering (if your utility supports net metering).
Thanks to net metering, you don’t need to rely solely on your day-to-day energy generation to offset your electric bill. Through net metering, the utility awards you credits in return for this electricity you send to the grid. These credits help pay for the electricity you use from the utility during the night, after a blizzard, or when you have higher-than-normal energy usage.
Professional solar installers, like Kasselman Solar, take your region's typical weather pattern into account. If your goal is to offset your electric bill, a little bit of bad weather won't affect you. A professional solar PV engineer will have designed your array to produce enough to account for that inclement weather.
Snow doesn't stick to panels for long
In order to maximize sun exposure, solar arrays are mounted at an angle. Combine this steep angle with the slick glass surface of the solar panels, and you have an object that snow just can’t stick to for long.
Array’s have one more thing that really makes it hard for snow to hang around. Heat.
The dark silicone cells of solar panels are designed to absorb heat from sunlight. Once any portion of a panel is exposed to the sun, a small amount of heat spreads throughout the panel and melts the snow. You see this same effect with a blacktop driveway, once a hole in the snow becomes exposed to the sun, it quickly grows. Once a bit of your array is clear and absorbing sunlight, the rest will follow.
Thanks to array design and installation, snow on panels rarely lasts for more than a few days. You’ll even see solar panels completely snow free while the rest of the roof is still covered in snow.
Snowfall is good for your modules
When snow melts off your array, it actually provides a free cleaning service. In drier parts of the United States, dust and dirt can build up on the surface of panels. This buildup can affect a solar array’s efficiency, meaning less production . Solar array owners in these areas are often forced to have their arrays washed to retain efficiency.
While the summer months offer more sunlight (thus, more energy production) than winter months, your panels actually operate more efficiently in colder weather. This is because cooler temperatures boost electrical conductivity, while hot temperatures diminish it. So the lower energy production in the winter may not be as much as you would think.
Fun Fact: Solar panels can convert any type of sunlight into electricity, which means light that’s reflected from snow to your array can help lower your electric bill even more.
Don't worry about cleaning
We recommend that you do not clean snow off your solar panels. The risk of injury to oneself or damage to your panels is not worth the small benefit. Your array is likely to be snow-free in a day or two, and any loss in production will likely be covered by production during those long summer days.
Bring on the snow
The next time you wake up to find a layer of snow on your solar array, don’t sweat the minuscule loss in production. Think of the convenient (and free) cleaning it will be providing your panels, and remember that it will melt away and slide off before you know it!