Do Solar Panels Work in Winter?

Thank you to John Livermore & Ryan Fitzsimmons from Boston Solar for providing their expert advice on solar panel efficiency during the winter…

Two of our most frequently asked questions are: “What happens to rooftop solar panels when it snows?” and “Will I have to shovel the snow off?”

There are some surprising upsides to solar panel operation in the winter…

• Panels actually help snow shed off the roof a lot faster. The southern orientation, dark panel surface, and electrical heat together help shed snow more quickly. One of our customers had a foot of snow fall on their roof. The next day it was 20 degrees F and by 9am the snow was completely removed from their panels.
• Snow often remains on the ground around a solar installation long after someone has cleared the panels. The sunlight reflected off the snow actually increases the electricity output of the panels.
• Cold temperatures actually increase the efficiency of photovoltaic cells and solar panel electricity generation.
• Melting snow serves to clean dust and pollen off the panels, slightly increasing panel efficiency.

Because most rooftop solar systems connect to the power grid, snow won’t interrupt your electric service. Snow also occurs during the months with the least solar electricity generation, so any snow cover on the panels will have a minimal impact on overall annual production. A recent Canadian article entitled, “Prediction of Energy Effects on Photovoltaic Systems Due to Snowfall Events” has verified the minimal electricity production impact of snow.

So, do you need to get up on your roof and brush the snow off of your panels? Clearly, no need to worry; instead, curl up with hot chocolate and a good book.