Blog: 1/31/11: Snow on Your Panels Getting You Down?

This entry is a re-publication of our recent Special Edition Newsletter.  We received some additional great tips from our customers after issuing the newsletter, which we have included here in blue.


With record snowfall across the entire country, chances are you may have at least a little snow covering your panels. We’ve recently heard from a lot customers whose arrays are entirely covered with snow.

The most important thing to keep in mind if you are worried about low production due to snow cover is that with annual net-metering, it’s really what your system produces annually (rather than daily, weekly or monthly) that matters. In other words, the production estimates you were given for your system were based on its performance over the course of the entire year, calculating losses based on historic weather data, estimating the impact of snow, rain and cloud cover.

Additionally, there is no need to worry about the weight of the snow on your roof. Your array was designed specifically for your roof after we measured your rafters and your roof span. Our systems designers, as well as your local building officials, have already made the necessary calculations to ensure that your roof can hold your shingles, panels, and more than the maximum amount of snow recorded for your area.

Next, be aware that photovoltaic solar panels do not have an internal heat source. When they are completely covered, they do not heat up. Exposing them to the sun always creates some electrical resistance (except in outer space, where it’s cold enough). It’s this resistance that creates heat. Therefore, as soon as a small portion of the panel becomes exposed, the snow and ice will start to melt more quickly. And if you happen to have adjustable-tilt ground mounts, putting them at their steepest angle will allow them to shed snow faster.

Finally, it can be comforting to remind ourselves that winter weather is an important part of Mother Nature’s master plan. Precipitation and snow are essential to our supply of clean drinking water. Try not to fret too much about your production; sunnier days are ahead. We are already beyond the winter solstice, days are getting longer, and you will soon see a jump in your energy production.

If you are determined to remove the snow from your panels, below are a few safety tips. Remember, climbing on your roof is extremely dangerous, especially in icy conditions.  Also, solar modules, especially Sunpower modules with “Anti-Reflective” coating are extremely fragile.  Special care must be exercised to ensure that the sensitive glass coating on these panels is not scratched.  You should not rest any sharp or abrasive objects on them, and do not use any abrasive object to scrape snow off of them.

Snow Removal from the Ground

1. If you can reach your roof with a non-abrasive device, try brushing the snow from just a corner or spot of your array. You can then try letting the rest melt naturally.

2. To reach further, you can purchase lengthening attachments to your non-abrasive snow removal device designed to safely remove snow from your panels. You’ll want to be sure the device you select cannot scratch the panels.

3. Please remember that any disruption of the snow and ice on your roof can result in a significantly heavy quantity of snow (with potentially sharp ice in it) coming down all at once. This can be more dangerous than you might think. Please exercise extreme caution and be sure that you have assistance present.

4. Try spraying a portion of the panels with cold water from a hose.  DO NOT use hot water, which would be a danger to both the glass and the cells.  Again, be aware of large portions of falling snow.

5. Try using a Roof Rake to gently remove a portion of snow from the panels.  Additional extensions can be purchased for higher roofs. These are specifically recommended for snow removal from solar panels.

Rooftop Snow Removal

1. Safety must always come first! Use extreme caution when climbing a ladder in the winter. Be sure to research ladder safety if you have not already done so.

2. Do not go on your roof unless you have a permanent anchor and can harness in.

3. Use only a non-abrasive device to gently push snow off the panels. You must be sure not to scratch the panels!

As a final disclaimer, please note that SunPower advocates that you allow the snow to melt off of your panels naturally. If you do damage to the panels while removing the snow, it is likely that this will void the panel warranty from the manufacturer.

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