InstallationQuestion 41 of 110
Why should supply and return ducts be sealed with mastic or listed tape at joints?
a.To increase gas pressure
b.To prevent air leakage that wastes energy and reduces delivered airflow
c.To hold refrigerant
d.To support the furnace weight
Explanation
Sealing duct joints with mastic or UL-listed tape prevents conditioned air from leaking into unconditioned spaces, which wastes energy and starves rooms of airflow. Leaky returns can also draw in dust or combustion products. California energy standards require duct sealing and testing.
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