How to Install a HVAC Ceiling Box
Attach the ceiling box securely to the ceiling framing with nails or screws. In many applications where your duct is laying on the ceiling members, you may want to attach a 90 degree elbow adjusted to a 45 degree angle or possibly even a 45 degree adjustable elbow to the round collar on the ceiling box and then attach your Flexible Duct or Sheet Metal Duct to the elbow. This will provide the best possible airflow for your systems efficiency. We recommend that you seal the seams with a duct sealant after installation to prevent any air leakage; this will increase the efficiency of your heating and air conditioning system and reduce your utility bills. See Duct Duct Installation Tips & Tricks for Flexible Duct or Sheet Metal Duct, depending on which type you will be attaching to.