The federal government has been actively pursuing a change in the culture to be more conservative with energy resources. Insulation, high efficiency windows and doors, heating and cooling equipment and caulking are just some of the components in homes that can increase efficiency. This guide discusses ways a designer can improve the energy efficiency of the building envelope within the context of the requirements of the 2009, 2012 and 2015 International Residential Code (IRC) and International Energy Conservation Code (IECC) for ceiling insulation and truss heel heights.