During the long, hot summer months, solar panels are often exposed to high thermal temperatures.
How hot are solar panels actually?
Household solar panels are tested at 25 °C (77 °F), so solar panel temperatures are typically between 15 °C and 35 °C, during which solar cells will produce maximum power generation efficiency. However, the temperature of the solar charging panel can reach as high as 65 °C (149 °F), at which point the efficiency of the solar cells will be hindered.
Most solar PV modules consist of silicon photovoltaic (PV) cells that are protected by glass panels and secured to a metal frame. These materials are similar to those that make up car windows and bezels – to get an idea of the heat of solar PV panels, think of a car parked in a parking lot in the hot summer. Windows and bezels will be hot to the touch, but there is little danger of fire.
Effect of temperature on solar panel efficiency
Users who consider solar panels often wonder, "Are the solar panels going to overheat?" Like any other electronic device, the performance of solar panels does deteriorate with increasing temperature – the laws of thermodynamics tell us that as heat increases, power output decreases, and this also applies to solar panels. Therefore, an increase in temperature means a decrease in the output of solar panels, which solar panel manufacturers call "temperature coefficient".
Manufacturers evaluate the sensitivity of their products to temperature in the form of temperature coefficients, expressed as a percentage per degree Celsius. For example, if solar panels have an efficiency of 17% and a temperature coefficient of -0.45, they lose 0.45% efficiency for every 1 degree increase above 25 °C. If the surface temperature of your roof rises to 30 °C (86 °F), the efficiency of the solar panels drops to 16.7%. If it is increased to 35 °C (95 °F), the efficiency drops to 16.3%.
How to counteract solar panel overheating
No matter which panel is used, there will always be some power output lost due to heat. However, there are several ways to mitigate the effects of high temperatures on solar panels. Solar panels are also usually installed a few inches above the roof, where there is actually airflow space underneath that helps carry heat away from the solar modules. One more thing, the temperature at which the solar panels produce the maximum conversion efficiency is 23°C.