The commercial roofing trend in recent years has been toward cool roofs – and for practical reasons. Among other benefits, cool roofs can increase the life of the roof and reduce operating costs.
Conventional flat roofs made from black or other dark materials absorb heat and transfer that warmth into the building. A cool roof is white or light in color and reflects light and heat. The result is a facility with lower air-conditioning costs in the summer and, for buildings that are not air conditioned (some warehouses, for example), a cooler and more productive environment for workers.
On a hot day, the surface of a black roof can be 70 degrees hotter than the air temperature, compared with only 20 degrees hotter for a cool roof. If a building has rooftop HVAC units, they’ll have to work a lot harder to cool the superheated air that’s hovering on a dark roof.
There has been some resistance to cool roofs in northern climates because they are thought to increase heating costs in the winter, as they don’t transfer solar heat to the building like black roofs. But a study by Lawrence Berkeley National Laboratory has found that in virtually the entire country, the summer air-conditioning savings of cool roofs are greater than any increased heating cost in the winter.
Besides energy cost savings, there are other benefits of cool roofs that make them attractive, particularly for commercial structures:
- Cool roofs tend to last longer because they suffer less thermal stress than dark roofs and because they help preserve the effectiveness of underlying insulation.
- Cool roofs help reduce the urban heat island effect (the tendency for cities to be several degrees warmer than surrounding rural areas), which promotes the formation of smog and greenhouse gases and contributes to human health problems.
- Installation costs for cool roofs are comparable to those for dark roofs, but have a shorter payback period because of the resultant energy savings.
Royalty Roofing is pleased to install the Duro-Last® Cool Zone® roofing system for our customers who are interested in energy-saving roof solutions. Click here to learn more. During the warm weather months, we’ll periodically post articles about cool roofing. Stay tuned!