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How well does solar power work in the winter? Can solar panels even make power in the cold winter months?
The short answer is YES, a solar panel system can work quite well in the cold, dark winter months! But there are many common misconceptions about how well solar systems can work in the wintertime.
The long answer is a bit more nuanced, so in this post, we’re going to break down the seven biggest questions people often ask us about how well solar power works in the wintertime.
- 1. Do solar panels work in the cold?
- 2. Do solar panels work in the snow?
- 3. Does solar work with winter weather and clouds?
- 4. How does your mounting type impact solar in the winter?
- 5. How do you clear snow and ice from solar panels?
- 6. What about Grid-Tied vs. Off-Grid considerations?
- 7. What is it actually like living with solar power in the winter?
- Solar power in the winter is possible!
1. Do solar panels work in the cold?
Yes, solar panels work quite well in colder climates. Even folks with frigid cold winters can enjoy the benefits of solar power. Photovoltaic solar panels (or PV) work because sunlight triggers the movement of electrons between layers within the cell’s structure. It is the sun’s LIGHT that is doing the work, not the sun’s heat. In fact, solar panels work a bit more efficiently at colder temperatures.
The bigger issues during the winter are the shorter days and less sunlight due to cloud cover. Even if we aren’t in the thick of big winter storms, the overall weather pattern trends towards low, thick clouds. The lower the clouds in the sky and the denser they are, the lower your solar energy output. This means a lower amount of energy produced and more time running the backup generator to keep the solar battery storage at a healthy level.
If you have a grid-tied solar system, cloud cover isn’t as big of a concern, but it does decrease the amount of energy you can produce, which means you’re feeding less into the grid. This will be reflected in your net metering and overall energy bill.
If you’re off the grid, cold isn’t a concern for your solar panel efficiency. It does, however, impact your battery efficiency. Most battery chemistries lose capacity as they get colder.
Some lithium batteries are particularly important to keep above freezing (many come with their own internal heaters for this reason). This is important to keep in mind as you’re planning out your utility space for an off-grid or backup power system.
2. Do solar panels work in the snow?
If your solar panels are covered completely in heavy snow accumulation, then no, not particularly well. But depending on the density of the snow cover, they can register SOME energy. For the sighted, it’s a bit like being blindfolded or closing your eyes. Imagine closing your eyes outside on a sunny day – you can still perceive light coming through the skin of your eyelids, but you can’t really see anything. It’s a bit like that for PV panels too.
The good news about the snow is that when you have some good sunshine after a heavy snowfall, the sunlight reflects off the white snow on the ground and boosts our solar production a bit. It’s always sort of nice to check our solar panel performance on those sunny days after a snowstorm to see just how much solar energy production we’ve got going on. It’s usually quite a lot!
We always make sure to remove snow from our panels any time they become covered, but I always like to check our charge controllers to discover how many watts our panels are registering before I uncover them. Typically, our panels can generate between 5-50 watts even through the snow (quite low, but not zero). After I clear the snow with a squeegee, they’ll continue working at their regular capacity given whatever other cloud conditions might exist at the time.
3. Does solar work with winter weather and clouds?
Winter weather can go beyond snow. Many days are thickly clouded, others have freezing rain, and yet others are abundantly sunny. How much sun you get and the quality of it really depends on your area’s weather patterns and latitude.
You can plug in your location here or here and get a general idea of what your sun potential / solar irradiance is. This is only one piece of the puzzle, but knowing the baseline potential of your particular location goes a long way to ensuring success with future solar energy systems.
Beyond that, your power generation can be greatly impacted by how you choose to mount your solar panels.
4. How does your mounting type impact solar in the winter?
Many people choose to mount solar panels to the roof. The roof makes sense for a lot of people, but it can also be a limiter to your power production. If your roof is angled away from the track of the sun in the sky, your ability to produce power decreases quite a bit. Beyond that, you’re limited to the pitch of your roof, meaning you can’t typically tilt the panels to match the sun’s position through the seasons. It’s also difficult to clear snow from roof-mounted panels, which can be critical for off-grid homes.
We have our solar panels mounted to poles. One of the mounts can tilt to match the sun through the seasons. The other can tilt AND swivel from side-to-side, meaning we can follow the sun along the horizon as it changes positions through the seasons. This helps us catch the southern-most sun in the winter and the northern-most sun during the summer (which helps us to run our air conditioning longer on long summer days).
Using adjustable pole mounts means that we can increase our power generation and keep it as high as possible during the short, cloudy winter days. It also makes it easier to clean the panels off with a squeegee when they are snow-covered.
There are other mounting types too, all of which have their pros and cons depending on your needs. I’ll detail those in a separate post (to be linked back here later).
5. How do you clear snow and ice from solar panels?
You want to make sure to keep your panels clear of snow and ice so the sun’s rays can get to the PV modules, but you also want to be safe. Here are some of our top tips on the best ways to clear snow and ice:
- Use a soft squeegee for clearing snow. We have this long telescoping pole and foam squeegee and highly recommend them. Some folks also like to use brushes, push brooms, or a roof rake, but we’ve had the best luck getting our panels 100% clean with a smooth squeegee.
- Do NOT use metal tools to clear snow or ice. Doing so could puncture the panels and potentially void any warranties you may have.
- Stay on the ground. If clearing the snow would require you to go up a ladder or walk on the roof, don’t. It isn’t worth the risk for a few extra watts.
I’ve had folks try to tell me to get heated mats or similar devices to melt the snow on the panels, but honestly, I haven’t been able to find any products that aren’t wildly impractical. Anything with an electrical heating element uses quite a bit of power to do its job, and using that much power when the panels are already snow-covered isn’t the best use of my time, money, or energy. For us, it’s far better to clear the panels manually.
6. What about Grid-Tied vs. Off-Grid considerations?
There is a pretty big difference in the wintertime needs of an off-grid versus grid-tied home.
For starters, power generation isn’t as critical for a grid-tied home since you still have access to grid power. You just won’t be putting power back into the grid at the same rate as you would during the summer months.
But for people living off the grid, like us, every watt of power you can generate during the winter is critical. This comes down to a few considerations:
- Buying the most panels/highest wattage you can reasonably afford
- Having the largest battery bank you can afford, relative to the wattage of panels you have
- Having a reliable generator
- Being able to keep the panels clear of snow and ice
- Being able to angle your panels for peak power production
The cost per watt in solar panels is almost always coming down, so getting enough wattage from solar panels is getting easier and more affordable all the time.
Battery technology is also improving, but your unique home setup and lifestyle preferences may impact the type of batteries you choose. It is also vitally important to size your battery bank and panels so that they work optimally together.
If you want to make sure your batteries and panels are proportionately sized, start by talking to reputable solar suppliers. We suggest starting with any of these companies (we have personal experience with all of them and highly recommend them):
- Shop Solar Kits: https://www.shopsolarkits.com
- Backwoods Solar: https://backwoodssolar.com/
- altE Store: https://www.altestore.com/store/
- Wholesale Solar (now called Unbound Solar): https://unboundsolar.com/
- Northern Arizona Wind & Sun: https://www.solar-electric.com/
- Midnite Solar: http://www.midnitesolar.com/
The battery chemistry you choose and where it gets stored (i.e. inside a heated vs. unheated space) is critical. Certain batteries cannot withstand freezing temperatures, and basically, all batteries experience diminished capacity the colder they get.
Off-grid homes also need a reliable generator during the winter. Even if you have a relatively large solar array and ample battery storage, there will inevitably be strings of cloudy days that never seem to end. And when that happens, you’ll need to run your generator to avoid discharging your batteries too deeply (which limits their ability to hold a charge and shortens their lifespan).
For now, we have a Honda 2000i (now the 2200i) and have used it reliably since 2016. There are many other kinds of generators out there (which I will link in a future post) but the two things you need to make sure of are that:
- You have a pure sine wave (inverter) generator.
- It is a reputable brand that can be locally serviced if needed.
7. What is it actually like living with solar power in the winter?
As of this writing (2022), this is our fifth winter season living with off-grid solar power. I won’t pretend to know what it is like for EVERY off-grid home. Each system design, home design, location, and household usage is unique.
But I CAN tell you exactly what our experience has been. We always have things to learn and new methods to try, but we seem to have a pretty good winter routine down at this point. You can read more specifically about it in these posts:
- Our Personal Experience With Off-Grid Solar Power in the Winter
- Cordwood Houses in the Winter: How Well Do They Perform?
We expanded our off-grid system back in 2020 and are loving the amount of power we’re able to get even during the shortest days around the solstice. You can read about our expansion in this post.
With our small system for the first two years, we made quite a few mistakes. Chiefly:
- We discharged our batteries too deeply.
- The batteries didn’t charge at a high enough voltage because the solar array wasn’t big enough, but also:
- We didn’t run our generator enough to compensate for the small panels.
So when we did our system upgrade in 2020, we had to get all new batteries because they wouldn’t hold a charge anymore. Since then, we baby them a lot more than we did the first time around.
Our solar array is nearly three times the wattage now, which keeps our batteries full even on short days. Our battery bank never used to reach “float”, or a full state of charge, during the winter. This past year our batteries “floated” on the winter solstice.
And when we have strings of cloudy and snowy days, we run the generator before the batteries can get too deeply discharged. We’re hopeful that this will help keep them in good working order for many more years than the first set.
So in short…
Solar power in the winter is possible!
Whether you choose grid-tied or off-grid solar, solar is a viable option for most people even during the dark, snowy winter months. Winter doesn’t mean you won’t have any power. It just means you need to carefully consider your unique situation.
Your latitude, local weather patterns, land orientation, and the size/type of solar power system you choose to install will all impact your solar experience.
If you’d like to dig in deeper, I invite you to subscribe below to get a free PDF guide to help you start going solar! You’ll also gain access to our entire FREE subscriber library full of helpful PDF guides to help you on your unique simple living journey.
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