Understanding How a Metal Roof Color can Save you Money
In order to understand how metal roof colors can save you money, we first need to understand how the sun transmits energy to an object like metal roofing. The energy from the sun can be broken down into three different components. 1) The Visible Spectrum 2) Ultraviolet light spectrum 3) The invisible spectrum. The visible spectrum represents about 46% of the sun's energy and this is what gives an object its color. The ultraviolet light spectrum only represents about 5% of the sun's energy and this part is what damages metal roofing paint. The invisible spectrum, represents about 49% of the sun's energy and this is what contributes to heat gain or build-up. Several studies show that by reducing the attic temperature of a house results in a lower demand for energy in the form of air conditioning your home.
One way of doing this is by installing metal roofing containing infrared-reflecting pigments in the paint. The infrared-reflecting pigments keeps attic temperatures two ways. The first way is by reflecting initially some of the sun's energy from the invisible spectrum. This method is most noticeable when you try to look at a shiny object during a sunny day and the glare is nearly blinding. The second way infrared-reflecting pigments work is by their ability to release some of the heat that isn't initially reflected. A good example of this is when you touch a metal object during a hot sunny day. Depending on the color and whether the object is painted with infrared-reflecting pigments in the paint, metal objects may seem to be hotter than others.
With all this being said, most consumers who are interested in installing the most energy efficient color on their house tend to lean toward a bare finish Galvalume® roof because they associate its reflectivity properties with its energy efficiency. Despite Galvalume® being very reflective, it lacks the ability to release stored heat back into the atmosphere once it heats up. Compared to a white metal roof that reflects and releases up to 59% of the sun's heat (white being the most energy efficient) a Galvalume® roof only reflects and releases 25% of the sun's heat. Obviously not everybody would like a metal roof, but hopefully this article helps you understand a little better how a metal roof painted with infrared-reflective pigments works.