Added Bonus: Installing Solar Panels over your roof can keep your building cooler
Author: Ben Schams
In 2017, Californians are becoming increasingly aware of the great range of benefits that installing a solar photovoltaic system on the rooftop of their home or business can offer. One particular solar benefit that isn’t so well known though, is that solar panels can reduce the solar heat gain of your roofing surface and keep the interior of your building cooler as a result. This benefit, which was confirmed in a study performed by researchers at the University of California San Diego Jacobs School of Engineering, was measured to reduce heat gain of the roofing surface by up to 38 percent. The researchers estimated in 2011 that the value of the energy savings associated with this building-cooling benefit would equate to approximately 5% of the energy production of the PV system over its lifetime.
This cooling benefit occurs in solar panel systems installed on racking that leaves an air space for convective cooling between the solar panel surface and the rooftop. Solar panels that are applied directly to the roofing surface, whether framed or frameless, may not offer any similar cooling benefit. An air space of a minimum of 2 inches and preferably 3 or more inches between the roofing surface and backside of the solar panel is highly recommended for rooftop installations of flat-plate crystalline-Silicon modules. The air-space will function not only to keep the roofing surface cooler (and the interior of the building as a result), but will also keep the solar panels cooler which will increase both their electrical production and useful life. This building-cooling benefit is truly an added bonus, as it is not accounted for by the energy estimation models that inform proposals in the industry.