Air ducts are one of the primary culprits of air leakage in buildings. Pressurized air in ducts will find any gap resulting in dramatic variations in air quality, airflow, temperature, and humidity. Inadequately sealed ductwork is also one of the biggest causes of HVAC systems that are seemingly impossible to balance. In multi-story buildings, this can also result in a ‘stack effect,’ where temperatures from the top to the bottom floor differ dramatically, and in extreme cases results in almost no airflow to the floors at the end of the ducting system. Building managers and air conditioning contractors then attempt to fix the problem, using excessive fan speeds.
Leaking air ducts are also one of the major reasons why many buildings feature oversized HVAC equipment and require booster fans to regulate airflow. Leaking ductwork can also pull or push air through cracks and gaps in buildings, which can amplify the effects of a leaking air barrier.