Over the past decade, energy codes have brought several changes with respect to improving the performance of the building enclosure both in design and construction. Most notable is the increasing importance placed on air-leakage through the enclosure and how this often-unknown value affects many of the energy efficiency metrics that define the performance of the building. In North America, there are currently multiple jurisdictions requiring Whole Building Air Leakage Testing (WBALT) as a code requirement. The most recent energy code to be adopted in many jurisdictions is ASHRAE 90.1-2019 or IECC 2021. These codes will either require WBALT or an increased presence of an air barrier consultant to review and document the air barrier from design through construction. While the requirements of the new energy codes are predicted to achieve energy savings, there are many questions to be answered. Through a review of historical advancements in air barrier requirements this presentation will provide lessons learned approach of what is to come as various jurisdictions adopt the ASHRAE 90.1 -2019 and IECC 2021 Energy Codes.

1. Review the theory and historical progression of air tightness requirements and understand the metrics that provide the baseline for levels of air tightness.
2. Understand what ASHRAE 90.1- 2019 and IECC 2021 Air Leakage requirements are.
3. Understand validity, impact, and relevance of air tightness codes and standards.
4. Understand whole building air leakage testing (WBALT) as compared to holistic enclosure consulting.