Do Solar Panels Work in the Winter?
The short answer is, yes they do!
The longer answer of course is, yes but for obvious reasons their output is lower than during the height of summer – days are shorter and snow will reduce or shut down output completely. We at ReVision Energy have been installing solar arrays in New England for over 10 years and have plenty of experience with designing solar arrays to endure everything winter can throw at them, from incredible cold to stacks of snow.
During our free site evaluation we use sophisticated solar path modeling equipment to estimate how much solar energy your roof or yard receives. Depending on your exact location, we ‘derate’ the predicted annual output based on the amount of snow your region receives on average. While there are always seasonal variations, over the course of your 40+ year solar investment, your system should produce very close to our estimate.
We should note that technical excellence is a key value at our company, and some solar installers are tempted to be, er, optimistic with their production numbers. We prefer to give honest and conservative figures, such that your solar array will be more likely to outperform, rather than underperform, what we think it will do for you.
Also note that because solar energy output is tracked on an annual basis (thanks to net metering), you stand to benefit from the higher overall summer output vs. winter. Since you always have the grid for a back-up, real-time 100% solar power to your home from your panels in winter is not critical.
Do solar panels work in the snow?
When a solar panel is covered with snow, it cannot produce electricity. However, solar arrays tend to shed snow pretty well (the panels themselves absorb the sun’s heat as well it’s light, they are mounted to face the sun, and are often on a slope). While it’s true that solar panels drop in production when they’re covered with snow, the percentage of overall yearly production lost is actually very small, which still makes them a good investment for prospective customers. We do not recommend that owners of solar systems clear the snow from their arrays as this could damage the array and is not covered under the warranty. Additionally, the panels themselves tend to be in difficult or even dangerous areas to access on the roof.
Do solar panels work in the cold?
Many people are surprised to learn that winter conditions can actually improve the performance of solar panels, further minimizing the drop in production due to snow on the panel or the loss of daylight hours. The photovoltaic (PV) technology in solar panels is actually able to more efficiently convert sunlight to power when they are colder. Further still, the panels are also able to catch the sunlight that reflects off the snow, adding to what the panels themselves could receive throughout the day.
What if I want to clear the snow from my panels?
Now, some customers have solar arrays that are easier to access and are willing to put in some effort to optimize their system for every possible ounce of performance. If you fall into this camp, there are a few tips we’ve received over the years we can share. If you have a roof rake, use it to clear the area beneath the panels so that snow has a place to slide to when it sheds from the panels. Without being raked, the sun will hit the snow and cause it shed from the panels and onto your roof, but with a little extra help this process will speed up. If you have flat plate solar hot water collectors, or solar photovoltaic modules, you can also attach a piece of foam pipe insulation on the edge of your roof rake and use it to gently clear snow from the actual panels (we’ve also heard that a few strips of duct tape to dull the edge of the roof rake works).
Be careful! While customers report success using this technique, any damage caused to your panels will not be covered under warranty. Absolutely do not try to clear the snow from collectors with the sharp edge of a metal roof rake (and never use any type of rake on evacuated tube collectors). Also, be mindful of your safety – a few extra hours of production in the shortest daylight times of year are not worth you injuring yourself.
We think your time is better spent indoors enjoying a cup of hot chocolate and looking forward to the next sunny day!