2025 was one of the hottest years on record, and each subsequent year will threaten to break that record. If you want to stay cool without making things worse, you might be tempted to use solar-powered cooling systems, but that requires solar panels to work when you need air conditioning the most: during heat waves. Unfortunately, they are subject to the “too much of a good thing” rule.
Although solar panels generally work best in direct sunlight, they ironically don’t work well at high temperatures – when the sun is strongest – because of the way they produce electricity. Basically, the sun (and to a lesser extent artificial light sources) generate particles called photons, and when they reach solar panels, they create electric fields that cause electrons to move, creating a current that ultimately produces the electricity we depend on. However, the more a material heats up, the more its molecules move, including electrons. Above a certain temperature, electrons move a little too muchmaking it more difficult to move the solar panel to where it needs to be, thereby reducing voltage (the pressure of electrical flow) and, therefore, efficiency.
Typically, solar panels work best at a temperature of 25 degrees Celsius (77 degrees Fahrenheit), and each degree Celsius above this value reduces hamstring efficiency by 0.5%. Heat waves can heat solar panels up to 65 degrees Celsius or more, reducing their efficiency by up to 25%. Although direct heat and sunlight can impact a solar panel’s performance, the lack of cooling solutions can make their temperatures even higher.
Keep Solar Panels Cool to Stay Cool
You may be wondering why solar panel efficiency tops out at 77 degrees. This is because these systems are tested at this temperature. Although we have little control over daily temperatures (despite humanity’s influence on climate change), we can customize our solar panel installations so that they don’t get too hot.
As heat increases, solar panels not only have to cope with the ambient temperature outside, but also the heat escaping from home roofs. However, installing anchors that provide a few inches of breathing space between the roof and the solar panel gives enough space to dissipate heat while also providing a passive convection airflow cooling solution. Additionally, while traditional logic dictates that you want to use dark-colored solar panels that absorb as much light as possible, solar cells made from light-colored reflective materials stay cooler and thus more easily maintain their efficiency during heat waves.
Although you can’t keep solar panels cool, you can mitigate some efficiency degradation by cooling the inverter (the component that turns electrical current into usable electricity). Installing the inverters in shaded areas, for example behind the solar panel, allows them to protect themselves from the heat and maintain somewhat optimal temperatures. If only you could keep solar panels cool by installing them in shaded areas, but that would defeat the purpose.
