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.

Learning Objectives

  • Identify the current code requirements related to energy performance of buildings.
  • Determine the differences between prescriptive and performance requirements.
  • Strategize how to best meet the intent of the code based on site specific conditions.
  • Understand the roles that insulation, air barriers, and vapor retarders serve in energy performance.