Rock the Residential HVAC Install Exam 2026 – Chill Out with Top Scores!

Friction loss refers to the resistance to airflow that ductwork creates as air moves through it. This resistance is typically measured in inches of water column (in. w.c.) and is crucial to consider when designing an HVAC system to ensure proper airflow distribution throughout the building. The other options, canvas collars, drive clips, and trunk duct, do not accurately represent the term for the known resistance to airflow offered by each foot of duct.