Air leakage in commercial buildings in the U.S. accounts for about one quad of energy annually. As the thermal resistance of commercial building envelopes continues to improve, the relative contribution of air leakage to heating and cooling loads is increasing. During this webinar meeting, Oak Ridge National Laboratory (ORNL) and Better Buildings Partner Arlington County, VA will discuss market trends and methods for addressing air tightness in buildings. Jessica Abralind (Arlington County, VA) and Philip Agee (Viridiant) will present results and experiences from air leakage testing at the County’s Solid Waste and Traffic Engineering Office. ORNL’s Dr. Diana Hun and Dr. Mahabir Bhandari will present recent research results on characterizing market trends in air leakage requirements, testing methods, and an examination of the energy cost savings potential for select building types.