Fact or Fiction: Solar Power is the Most Efficient During the Winter Months

Solar panels were, are, and will always be associated with the sun. Because of this, it’s natural for just about every homeowner to think solar panels perform at peak efficiency and produce the most electricity during summer, the sunniest time of the year. Even major solar companies across the nation spread the message through advertisements, sales pitches, eBooks, blogs, and consultations that summer is the best time to go solar! But is that really true? Should homeowners associate the winter with low solar production, efficiency, and savings? Well, in today’s post we’ll be looking at the truth behind going solar in the winter.

Do Panels Perform Better in High or Low Temperature?

We all know that winter equals cold weather. The national average temperature in January of 2020 was 35.5 degrees Fahrenheit. For most states, the difference between average summer temperature and average winter temperature can be more than 45 degrees! But what do all these temperature statistics mean for a homeowner considering solar?

While it may seem counterintuitive, high temperatures can cause solar panels to be less efficient because of the law of thermodynamics. Just like a computer or phone, solar panels can overheat. This means that the hotter the temperature the worse the panels will perform. Thus, panels are actually more efficient during the colder fall and winter months. But how much of an effect do temperatures have on overall panel efficiency? Well, the solar industry typically tests its panels as if they were in a 25 °C or 77 °F environment. The average panel will drop by about 0.05 percent for every degree Celsius over that tested temperature. If panels reach an internal temperature of 35 °C (95 °F), they will produce power with .5% less efficiency than their original grade. For most states, this decrease in efficiency only occurs during the summer months, meaning that panels are technically more efficient during the winter. Temperature plays the biggest effect in hot states like Arizona, California, Florida, or Nevada, where panel temperatures can exceed 95 °F for almost half the year. During the winter, all solar owners will avoid any losses to solar panel efficiency and monthly electricity bill savings independent of the state they live in.

Originally, solar panels performed poorly in freezing temperatures. However, the solar industry was quick to develop a layering design to protect solar panels’ internal temperatures from getting too low. Through the use of tempered glass, aluminum casing, and a steady back sheet, solar panels can stay at the ideal internal temperature of 40 to 55 degrees Fahrenheit even during the coldest winter storms. However, scientists have yet to discover a way to keep panel’s internal temperatures cool during the hotter summer months. Thus, the winter months should not scare homeowners away from going solar, since lower temperatures are actually ideal.    

Panels don’t Produce Energy in Cloudy Weather…

Well, if cold temperature doesn’t play an effect on solar panel efficiency, clouds from winter storms must, right? It’s a common misconception that solar can’t produce energy when sunlight is blocked by clouds. However, just how you can get sunburned on a cloudy day, solar panels still produce energy when the sun isn’t beaming bright. This is because solar panels don’t require direct sunlight to produce energy. Unfortunately, indirect sunlight is not as effective as direct sunlight, which means that solar panels will produce 10-25% less electricity on a day that has a large quantity of cloud coverage.

Despite this unfortunate truth, there are some situations in which clouds can actually increase solar panel energy production. Some winter days are filled with individual clouds that pass slowly in the open sky. These lone clouds reflect direct sunlight, causing more of a higher concentration of light to hit nearby solar panels. Thus, for a brief amount of time, a residential solar system can produce a burst of extra electricity. This is called the cloud edge effect and commonly occurs during colder fall and winter months of the year. Although homeowners should never depend on lone clouds to boost their energy output, they can have peace of mind knowing that clouds don’t always have such a negative effect on solar production!

Doesn’t Snow Buildup Block Panel Productions?

Dozens of states are accustomed to winter storms that can dump inches and even feet of snow in less than a day’s time. When the snow from a storm builds up on a roof, any solar panels are covered in a blanket of snow. This external covering is one extra layer for the sun to pass through and will even reflect a good portion of sunlight that will never reach the panels. Depending on the depth of snow, panel production typically sees a 20-30% loss when covered in snow. That is a massive amount of savings being lost, especially if you live in a place where it snows throughout the winter. Luckily, the surface of solar panels tends to heat up throughout the day. This causes any built-up snow to melt quickly and disappear throughout the day. In some locations, snowfall might be high enough that solar panels do not have enough time to melt all that snow buildup. In these locations, we suggest that homeowners buy the appropriate tools that allow them to safely remove excess snow from the solar panels. All in all, snow shouldn’t have a long-term impact on the effectiveness of your panels.

So, What’s the Verdict? Are Solar Panels More Efficient in the Winter?

When you break it all down, the blog post’s original question is truly a fact, but don’t let that trick you into believing a newfound fiction:

Fact – solar panels are more efficient during the winter.

As we mentioned, solar panels perform at peak efficiency when they have an internal temperature of 40 to 55 degrees Fahrenheit. All panels are able to maintain this ideal temperature during the winter due to their layering design. However, high temperatures during the summer can cause panels to overheat and drop slightly in efficiency. Thus, solar panels are most efficient during the cold winter months.

Fiction – solar panels produce more electricity during the winter.

Although panels are more efficient during the winter, they spend less time in direct sunlight. Because of the United States’ position in the Northern Hemisphere, summer months have longer days than the winter months, which mean more overall sunlight. The sun also passes higher in the sky, which is more beneficial for producing electricity. All in all, the slight boost in efficiency during the winter can’t make up for the increased sun exposure and angles during the summer.

Our Recommendation at Blue Raven Solar:

At Blue Raven Solar, we believe that there is no better time to go solar than now! Independent of season, sun exposure, or state, homeowners should choose to go solar A.S.A.P. to take advantage of competitive prices, an extended federal solar tax credit, and any other local or state benefits. If you’d like to determine whether solar is right for your home and situation, we provide a free quote to all eligible homeowners. This quote will allow you to visualize what solar would actually look like on your home, how much it would cost, and how much it could save you over the course of several decades. If you like your solar quote and its savings projections, you can begin your solar journey and become a part of the Blue Raven Solar Family. We only use the highest quality and most durable panels. We also offer a 24-month production guarantee, a 10-year workmanship warranty (which protects our customers against any of the threats mentioned in this post), and a 25-year panel warranty. It is our objective to make going solar as simple and pain free of an experience as possible. So, get a free quote today, and we’ll get your panels installed to produce electricity and save you money year-round.  

Sources:

https://allseasonsolar.net/clouds-weather-affect-solar-panels

https://nmsolargroup.com/effects-clouds-solar-panel

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