US Energy Secretary Steven Chu recently made some very good comments about the value of reflective metal roofing in terms of reducing energy costs for our country. The only problem was that he made reference only to roofs that are White in color. This is a pretty significant omission especially considering the current US federal tax credit available for homeowners who buy roofs that are reflective but not necessarily white in color.
Today’s metal roof choices often offer reflective pigment in their coatings so that high reflectivity is available even in colors as dark as brown and black. Homeowners can have energy efficiency without having to choose a white roof. While white roofs are reflective, their drawback is that they are also very prone to dirt and dust – they do not stay white forever. Once they get some dirt accumulation, the look gray and dingy which reduces their reflectivity significantly.
Additionally, metal roofs which have a formed thickness and an airgap between the metal and the plywood or OSB roof decking have even greater energy efficiency. That airgap blocks heat transfer by conduction. Some studies have shown the airgap to be even more effective in terms of energy efficiency than color or reflective coatings.