Rooftop Solar Cools Roofs Study Shows

We need to reduce our greenhouse gas emissions and rooftop solar is a proven method. Beyond producing electricity, rooftop solar shades roofs which in turn lowers building temperatures. This added benefit can help save homeowners and businesses thousands in heating and cooling costs. According to a study from UC San Diego published in the Journal Solar Energy, rooftop solar reduced the amount of heat reaching the roof by 38%. 

Shielding roofs from intense heat can reduce overall air conditioner usage and reduce green-house gas emissions. This is great news for home and business owners as the world heats up.

According to research lead Professor Jan Kleissl of UC San Diego Jacobs School of Engineering, “As solar panels sprout on an increasing number of residential and commercial roofs, it becomes more important to consider their impact on buildings’ total energy costs.” The researchers estimated that the air conditioning savings from solar panels are equivalent to getting a 5% discount on the solar panels. 

The study used thermal imaging cameras of the ceiling of the Powell Structural Systems Laboratory to measure the heat coming off of three zones; a flat section of solar panels, a tilted section of solar panels, and an area of roof with no solar. The image below demonstrates the dramatic difference with the tiled area being the coolest.

The image on the left shows the solar configuration on the roof used in the test. The image on the right shows how flat, tilted, and no panels differ in heat. Source: UCSD

Why the different results between the flat and tiled solar panels? While the flat panels remained far cooler than no panels at all, the smaller gap between the flat panels and the roof can trap warmer air. By contrast, the tilted solar panels allows for a ample airflow between the panels and the roof. In addition, tilted panels usually have a more direct angle for solar energy collection in areas other than the equator. 

While the savings depend on how hot the local climate is and how much of the roof is covered, it is clear that as the world warms up that this is a win-win solution for solar energy. The added reduction in heating and cooling costs is a wonderful benefit to switching to rooftop solar. It’s a no-brainer.