For the past decade plus, energy codes continuously increased their requirements for energy efficiency of buildings. Codes began by increasing insulation requirements and recently added an air barrier requirement to reduce air leakage of conditioned air.
The codes include prescriptive and performance requirements; however, the prescriptive requirements are what most designers utilize. Following the prescriptive requirements without consideration of the environmental conditions, both exterior and interior, can result in unintended performance of wall and roof systems. This article will discuss the current state of the code requirements, both prescriptive and performance, as well as when prescriptive requirements may result in inadequate performance.