During the long, hot summer months, solar panels are often exposed to high heat temperatures.

How hot are solar panels actually?

Home solar panels are tested at 25 °C (77 °F), so the solar panel temperature is usually between 15 °C and 35 °C, during which time the solar cell will produce large power generation efficiency. However, the temperature of the solar panel can reach as high as 65 °C (149 °F), at which point the efficiency of the solar cell will be hampered.

Most solar panels consist of silicon photovoltaic (PV) cells that are protected by glass panels and held together with a metal frame. These materials are similar to those that make up the Windows and bezels of cars - to understand the heat of solar panels, think of a car parked in a parking lot on a hot summer day. The Windows and borders will be hot to the touch, but pose little risk of fire.

The effect of temperature on the efficiency of solar panels

Users considering solar panels often wonder, "Can solar panels overheat?" As with any other electronic device, the performance of solar panels does decline as the temperature increases - the laws of thermodynamics tell us that power output decreases as heat increases, and this also applies to solar panels. As a result, a rise in temperature means a reduction in the output of solar panels, which solar panel manufacturers call the "temperature coefficient."

Manufacturers assess the sensitivity of their products to temperature in the form of a temperature coefficient, 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% of their 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 will drop to 16.7%. If it increases to 35 °C (95 °F), the efficiency drops to 16.3%.

How to offset solar panel overheating

No matter which panel is used, there will always be some loss of power output 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, and there is actually a airflow space underneath to help carry heat away from the solar panels. One more thing, the temperature at which solar panels generate large conversion efficiencies is 23°C.