A White Roof is a Cool Roof
I think we all have walked on asphalt pavement barefoot at one time or another. Growing up surfing in Florida, we build up calluses just to handle our favorite break’s hot parking lot and scorching sands. We learned something really quick: The darker the pavement, the more it burns. I have been dumb enough to try this: A barefoot jump onto an asphalt roof to retrieve a Frisbee. It wasn’t pavement hot, it was lava hot.
When it comes to selecting our roof and roofing material, color has a huge impact on the overall thermal efficiency. A white roof is a low-tech, low cost solution to improve efficiency. By reflecting the solar energy, it never penetrates the roof subsurface elements. The roof is literally the first line of defense for your building. If you don’t heat it up to begin with, you don’t have to cool down your interior as much. You save energy.
In 2011, The University of Melbourne in Australia conducted a field test and performed computer simulations/models to determine just how much a white roof can reduce thermal absorption. The tests concluded that white roof products reduce indoor temperatures significantly during the day. They also reduced average temperatures inside at night, proving that the thermal emittance, that is the roofs ability to release and not store heat, had an impact when the Sun wasn’t shining as well.
The Florida Solar Energy Center conducted a residential energy test 16 years ago that concluded that energy efficient construction mixed with white roof technologies can result in a 23-40% decrease in cooling costs during the hottest summer months, yet 75% of homes still use standard dark asphalt shingles!
The choice of color for a roof is often a question of taste and aesthetics, but when choosing something as simple as a color can mean a difference in thousands of dollars over the lifetime of your building, it is worthy of consideration. If white is not an option, consider lighter shades. The lighter the color, the the more you save.