Our premium HVAC Duct Ceiling Boxes or C-Box, are used to attach a register in the ceiling to supply air in any room. Our C-Boxes are manufactured from the high quality galvanized steel. Sizes listed are the box opening widths, then the round size as the last dimension. They have a plaster ground flange attached for easy finishing to your plaster or drywall.
Duct Installation Tips & Tricks — attach the ceiling box securely to the ceiling framing with nails or screws. In many applications where your duct is laying on the ceiling joists or framing, 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 within your duct system efficiency. We recommend that you seal ALL duct seams with a duct sealant after installation to prevent air leakage; this will increase the efficiency of your heating and air conditioning system and reduce your gas and electric bills. See Duct Duct Installation Tips & Tricks for Flexible Duct or Sheet Metal Duct, depending on which type you will be installing with.