Bill Shock: A Few Reminders for Solar Customers in the Winter Months

lower solar panel productivity, Bill Shock

The Winter Solstice, December 21st, represents our shortest day of the year. These last few weeks and the weeks ahead represent the least amount of daylight hours we will get for the entire year. If you have solar panels installed on your property, you might have noticed an uptick in your energy use while also seeing a downward trend in the productivity of your solar panel system. This usually means that customers like you start getting energy bills that are significantly higher than what they saw during the spring, summer or fall. This is what we’d like to call Bill Shock. Have you experienced Bill Shock this year? Do you wonder about your solar panel productivity? We’ve got answers to your questions.


What is Bill Shock?

Let’s say you decided to go solar during the winter and your solar panel system was installed in April, just a week or two after the Vernal Equinox, when we start to see our longest daylight period. Your energy bills were significantly lower in April and May, with June and July (the months around the Summer Solstice and the longest days of the year) bringing home $0 energy bills. You and your family are absolutely delighted with your new system! As August, September and October roll in, you are still seeing dramatically low energy bills. But then your November bill is pretty high because the sun is setting earlier. Then there is a little bit of snow in early December, and the days are at their shortest as we get close to the Winter Solstice. You get your December energy bill and it’s the highest it’s been since your panels were installed. Perhaps it’s even as high as it was before you had them installed!

This is a time when customers start to wonder: did my panels break? Are they faulty? Am I really saving money after all? This is Bill Shock and we totally understand: it’s hard to get a $100 energy bill after a few months of not having to pay anything at all. Chances are, your panels aren’t malfunctioning. Furthermore, we are fairly confident that you are indeed saving on your energy usage. That is because we don’t measure the productivity of your system from month-to-month, but year-to-year.


Why the Big Bill in December, January and February?

There are a few things that are absolutely guaranteed in life: death and taxes and, if you live in New England, snow. Some winters are worse than others, but all winters come with snow, and snow sits on solar panels, blocking their ability to convert sunlight into energy. The snow does indeed melt off of your panels, but time that snow sits on them during the day is time when panels cannot do the job you have put them there to do. Our peak snow months of December, January and February mean low productivity times if you have solar panels.

Living in the higher latitudes, the sun’s path and angle are lower in the sky during these winter months, while our days are incredibly short. Between the Summer Solstice and the Winter Solstice, we lose a little over 6 hours of daylight. That makes a significant difference to the productivity of your panels! Try as they might, your panels simply will not be able to perform at their peak performance during this time of year, and this results in an increase in your monthly bill.


Keeping an Eye on the Big Picture

While creating a panel system that works best for you and your property, we make a forecast for the productivity of your system based on multiple factors, including your energy usage as well as your specific panels. Just as the weather comes and goes with the seasons, your energy use does, too. Many customers consume the most energy of the year in the Summer (thanks to running the AC, the kids being home, and other factors) and the Winter (family entertaining, the heater on, etc), while the Spring and the Autumn often show lower use (likely because heat/cooling systems are off and windows are open). When looking at the entire year’s-worth of energy usage, we have found that our panels save our customers money overall from year-to-year over traditional utility companies. Underperformance in the winter is often greatly outshined by peak performance in the summer months.

1/18/2019 – Edited to Add: To put it into real numbers, here is a typical graph of a New England solar system. This customer is located in Carver, MA. Have a look at the difference between January and July. Production in January 2018 was just 213 kWhs. Production in July 2018 was a whopping 2091 kWhs.

Solar Production over 1 Year

What does it all mean?

We acknowledge that Bill Shock is real and that it can be a disappointment for customers who are just getting used to their solar panel systems. There are plenty of ways to mitigate the higher energy consumption and lower energy production of the winter months by following tips and tricks for getting the most out of your energy. Take heart in knowing that after tomorrow, our days will start to get longer again, the sun angle will get better and the sunlight will get warmer and stronger. Our best days are ahead of us, and that’s always a great thing!

Want to kick-start your solar energy goals for 2018? Submitting a quote request today means you’ll have your panels up and functioning just in time for Spring!


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