Air Barriers vs Vapor Barriers

Condensation Air Barriers Insulation Energy Use

Course Description

Most professionals in the building industry acknowledge that the concept of vapor control is difficult. So it’s not really surprising that there’s confusion surrounding vapor barriers. What’s interesting is that the root of a lot of that confusion has to do with some incorrect assumptions not about vapor control, but about air control and the role of air barriers in our buildings. Most of us assume that the purpose of air barriers is to provide comfort and energy efficiency. And this is true! Airtight buildings are much more energy efficient and tend to be much more comfortable than leaky buildings. But air control is also important for condensation control, which is critical for building durability. Vapor control is quite different in that the only reason to care about vapor control is building durability. This course examines the differences between air barriers and vapor barriers and brings some much-needed clarity to when each is required.

Course Instructor Christine Williamson

Course Length 15:45

Published 22 Jul 2022

Please note: viewing this course and completing this quiz do not currently count towards AIA CEU credits.

Keywords: building science, insulation, energy, energy efficiency, exterior insulation, condensation control, air barriers, vapor barriers


About Building Science Fight Club

Christine Williamson - Assoc. AIA

Building Scientist | Instructor

Christine Williamson has spent her career in building science forensics, discovering why buildings fail and working with owners, architects, and builders to remedy the problems. She is the founder of the Instagram account @BuildingScienceFightClub, an educational project that teaches architects about building science and construction.