A Cup of Joe: Airtightness

Airtightness targets, or maximum airtightness levels, are a metric for assessing building performance. To set a target, it is critical to understand that building airtightness tests measure the air leakage through the entire building enclosure (roof, walls, slabs, windows, doors, vents, etc).

In this episode of A Cup of Joe, Joe Lstiburek reflects on his experience establishing airtightness standards and reviews how tight building enclosures should be.

Higher levels of airtightness, often verified through testing, are becoming increasingly the new normal because it can affect energy use by impacting the building’s heating and cooling requirements.

When air leaks into or out of a building, the enclosure’s role as an environmental separator is compromised—the inside gets out or the outside gets in. That can lead to comfort complaints due to drafts, poor humidity control, dust, noise, and as poor indoor air quality. For this reason, airtightness must be considered as part of a whole building approach that considers all aspects of performance.

DELTA®-VENT SA, vapor permeable air- and water resistive barrier prevents moisture from getting into buildings. Its vapor permeability and air tightness makes DELTA®-VENT SA ideal for building and maintaining healthy and comfortable interiors while letting moisture out and improving energy efficiency.


About Dr. Joe Lstiburek

Dr. Joe Lstiburek is the founding principal of Building Science Corporation, one of the most influential, innovative, and respected building science firms in North America. Dr. Lstiburek’s work ranges widely, from providing expert witness testimony to overseeing research and development projects to writing for the ASHRAE Journal. His commitment to advancing the building industry has had a lasting impact on building codes and practices throughout the world, particularly in the areas of air barriers, vapor barriers, and vented and unvented roof assemblies. His commitment to education earned him the hailing, “the dean of North American building science” by the Wall Street Journal. Dr. Lstiburek holds a Bachelor of Applied Science in Mechanical Engineering, a Master of Engineering in Civil Engineering, and a Doctor of Philosophy (Ph.D.) in Building Science. Get the full scope of Dr. Lstiburek’s work, accolades, and contributions to the industry over at Building Science Corporation.