More than 70 percent of buildings in the U.S. are over 20 years old. This is problematic since the majority of these buildings are not designed to meet current insulation or air infiltration requirements. In an attempt to reduce operational costs, many building owners are choosing to renovate and upgrade the thermal efficiency of their buildings to reduce energy costs. To promote this effort, leading U.S. corporations, universities, and government agencies have committed to reduce energy use by 20 percent over the next 10 years through reduced carbon pledges, such as the 2030 challenge.