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Understanding the Effects of Heat on Solar Panel Performance

Updated: Jul 6

Summer might seem like the most ideal time for solar energy panels, and the abundant number of sunshine hours are certainly great for solar-owning homes. However, homeowners and businesses that have a solar array should be aware that high temperatures can also impact your solar panels’ efficiency. Here’s a quick overview of how the heat can affect performance, and tips for what you can do to minimize the detrimental effects.

How Solar Panels Work

The way that a solar energy system works is pretty straightforward. Your solar panels, mounted on a roof, on the ground, or somewhere else where they get enough sunlight exposure, will collect energy during sunlight hours. Captured light energy is converted into electricity to power your home or whatever else you need. For systems with a battery backup, that energy is stored until you need to use it; for grid-tied systems, the energy is either used immediately or is transferred to your local power company for others to use, providing a “credit” for when you need to pull power from the grid after the sun goes down. Based on that, it might seem like summer is the ideal time to capture solar energy, but it’s the light—not the heat—that creates electricity.

How Heat Affects Energy Conversion

The optimal temperature for solar panel efficiency is about 77 degrees Fahrenheit (25 degrees Celsius). When the temperature outside hits 90 degrees or above, the efficiency of your solar panels actually goes down. Hot, dry summer air can lead to about a 10% to 25% drop in efficiency, a number that manufacturers quantify in the “temperature coefficient.” This number identifies the decrease in output—for example, a temperature coefficient of -0.25 means that output power goes down by a quarter percent for every degree that the temperature rises above 77 degrees. Keep in mind that the average temperature of a dark roof in summer could be significantly higher than the outside temperature, so a 90 degree day could mean a roof temperature of 140 degrees or more.

Your system will need to capture even more sunlight on hot days to convert the same amount of electricity from day when panels work at peak efficiency. Fortunately during the summer, sunshine hours are longer so you should have more time to capture solar energy to make up for efficiency gaps.

Other Ways to Maximize Energy Capture in the Summer

In addition to the longer hours that you will have to capture solar energy, there are some other strategies you can use in the summer months to get the highest level of efficiency possible. Talk to your PRVL Energy installer about the ways that we ensure efficiency with proper installation. You can also try running high-energy appliances like your dishwasher and washing machine during the daytime when your system is actively collecting power.

To find out how you can get solar panels installed and get all your questions answered, call PRVL Energy today.