Solar Maintenance Blog

How Winter Affects Solar Panel Performance

November 11, 2019

The more hours of sunshine a solar photovoltaic (PV) panel receives, the more clean power (and electricity bill savings) it can generate. This explains why states further south generate more solar energy per home than northern areas. But even the most northern states have plenty of year-round sunshine – especially during the summer months when the sun is out for the most hours.

However, what happens to your own solar savings when winter finally arrives? After all:

  • The days get shorter, meaning there are fewer hours during which to generate clean electricity
  • The sun sits lower in the sky, which means that your solar panels may receive less direct light  
  • Snow accumulation on your panels can block out the sun completely

And in rare cases, your solar panels can become damaged by extreme weather events.

Whether you live in a region with relatively mild winters or one with more significant winter weather, does solar power make sense in the winter?

The answer is yes. Let’s explore why.

The Truth about Solar Panel Performance in Winter

Because of the factors outlined above, solar PV output is lower during the winter than it is during the summer. However, the difference is significantly less than you may be thinking.

It’s true that solar panels don’t receive as much direct sunlight when the days get shorter and the sun sits lower. 

It’s also true that snow buildup can block out your solar panels entirely. However, with their slick surfaces, dark colors, and tilted angles – most PV modules actually don’t accumulate much snow. It just melts away on its own. And if it doesn’t, you can always purchase a low-cost “solar roof rake” designed to remove snow without damaging the panels.

Finally, bad weather can cause roof leaks or otherwise damage your roof enough to require a complete roof replacement. For rooftop solar owners, this means your panels need to be safely removed and replaced for repairs. If your panels require removal in order to fix or replace your roof, be sure to visit our Solar Panel Removal and Replacement page.

Despite these issues, there are 2 important reasons why solar power is a great investment all year long – even during the winter months.

1. Solar Output and Temperature

PV panels require the sun’s light, but don’t do as well with too much of the sun’s heat. In fact, the colder it gets, the more efficient your solar panels become. This efficiency boost isn’t enough to completely counteract the shorter days and less direct sunlight – but it definitely helps.

2. Solar Savings Never Disappear 

As long as the sun is shining, your solar panels are saving you money. This is true even on December 21 – the shortest day of the year!

Again, those savings won’t necessarily match what you’d normally expect during the summer months. However, a well-maintained system can generate a surprising amount of clean power and lower bills regardless of the season. And when added to your annual savings, your wintertime production helps to shorten the payback period of your solar power investment.

What Happens If Your Solar Savings Don’t Rebound?

Solar energy generation will vary naturally throughout the year – with summer time giving you the most power, and wintertime the least. So don’t be alarmed by seasonal changes in your solar PV system’s performance. In fact, your installation’s solar output will vary minute by minute – simply due to changing weather conditions throughout the day.

However, if your solar installation’s performance dip is much larger or longer than normal, this could be an indication of some other cause, like a broken solar meter or a glitchy solar monitoring system.

Either way, you are losing potential utility bill savings with every sunrise. Worse still, you’re also creating a larger carbon footprint if a greater portion of your power consumption comes from grid electricity (generated by burning dirty fossil fuel).

If you need help identifying and troubleshooting the underlying problem, we recommend following the 2 steps below:

  • Try our free solar meter checklist. You’d be surprised how many issues can be resolved with this simple DIY step.
  • Contact us today to connect with one of our solar experts. With the majority of solar performance issues, we’re able to help our customers troubleshoot the problem remotely.

The sooner your installation comes back online, the sooner you can reclaim your solar savings and protect the long-term ROI of your clean power investment.

If you still have questions about wintertime solar performance, contact us directly using our contact form.

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