Solar panels are built to be extremely durable, and very, very tough. Quality solar panels are more common than cheap and unreliable panels so when shopping it’s easy to differentiate between panels. One thing panels by their very nature have to be exposed to is weather, and we all know what weather can do. Because solar panels are exposed to weather so frequently they are put through a variety of different rigorous testing to ensure they can take it. This earns them a variety of different ratings and certifications.
Let’s face, weather can be a dangerous SOB/. We’ve all seen the damage extreme weather can do. So before I address how weather affects solar panels I want to separate two very different types of weather to avoid any confusion. First and foremost any devastating weather, like hurricanes, tornadoes, and extreme floods are plenty capable of destroying your solar panels, just like they are capable of destroying your home. In general you are going to have a lot bigger worries than your solar panels should this weather come about. To be clear I am saying this weather can damage panels, but this isn’t everyday weather. It’s important to distinguish between everyday weather and disastrous weather.
Everyday weather ranges from a light sun shower to a thunderstorm, but nothing that commonly causes massive damage to homes, vehicles or nature itself. Now rain water, even heavy rain, will not damage or affect your solar panels. In fact rain can often clean dust and debris from your solar panels, so it’s a positive. The wiring from your solar panels is also weatherized and waterproof.
Severe winds have the potential to damage panels the same way they have a potential to blow your roof off. What’s really important is using a reputable installer. When installed correctly solar panels will withstand strong winds without taking damage. In 2012 it was found the extreme winds of Hurricane Sandy did nothing to damage solar panels across the east coast, and panels that were professionally installed, remained installed.
For a lot of localities hail will be a rare occurrence, but it can happen. Hail is the bane of vehicles owners everywhere, but is it the bane of solar panels? Hail is unpredictable, and ranges in size from penny to soft ball, so it’s hard to give a definite answer. In some extreme cases large amounts of large pieces of hail can damage a solar panel. This is actually extremely rare though. Most quality solar panels in the United States are rated UL. UL is a weather rating that is assigned to solar panels when they meet certain objectives, and being hail proof is one such objective.
To get that UL rating hail is simulated with steel balls approximately 1 inch around. These steel balls are hurled at solar panels at terminal velocity with the panel at a 90 degree angle. It is worth nothing that UL is a safety rating, meaning the glass may crack, scratch, and break, but will not exploded.
Last but not least we have lightning. Having solar panels on your roof does not make your house a lightning rod, so lightning strikes on solar panels are extremely rare. Solar panels are most likely going to be destroyed if struck by lightning. There is really no way around that. However, your house overall will be safe if the panels and your grid tied system are installed in accordance with the National Electric code. This is another reason to hire a legitimate solar system installation company.
Weather can degrade the performance of your solar panels in a variety of different ways. First and foremost let’s talk about the most obvious, overcast conditions. Overcast conditions vary greatly from a little misty to dense overcast, and everything in-between. Each of these conditions can hamper solar performance, because they place a layer between the sun and your solar panels. Typically you won’t notice a degraded performance until you get to a mostly cloudy situation. After that you could start seeing a drop in solar efficiency. Once you get to overcast and densely overcast you could be looking at a 60 to 90 percent degradation of performance.
Another weather condition that destroys solar performance is snow. A snow covered solar panel is essentially degraded to point of being useless. So after any snow storm it is advisable to go out and clear the snow from your panels or you’ll be waiting for the sun to melt the snow, which leave you without solar power until the late afternoon.
High temperatures can actually affect the energy production and efficiency of a panel. The amount of electricity produced per panel can actually drop when the panel reaches extreme heats. Experiments have found that panels lose roughly 1.1% of output for every degree above 107 degrees Fahrenheit. This isn’t measured from the temperature outdoors, but from the panel itself. Since panels are designed to be in the sun, and are dark colored they do get extremely hot, so instead of cranking out more power in the summer you might be cranking out less.
Colder temperatures have been found to be the better environment for solar panels. Power production doesn’t increase per say, but it remains efficient throughout the day. The perfect day from a solar power perspective is a cold sunny day. However, the winter tends to have shorter days, so less power is generated overall.
Weather can create some side effects you may have to deal with. For example strong winds may not affect the panels by themselves, but wind can kick dust up. Dust and leaves kicked up and carried by wind can form a fine layer of junk on your solar panel and lower efficiency, meaning you may need to clean your panels. There is also limbs and debris that can fall from nearby trees, potentially damaging your solar panels. So you should take care to trim trees near your solar panels to prevent this.
The weather effects on solar panels are truly minimal. Solar panels are generally quite tough, and built to last longer than your roof in the outdoors. Just apply a little common sense here and there and your panels will be right as rain.