How To Make A Return Plenum In Floor Joist

Return air duct is connected together using s slips and drive cleats.

How to make a return plenum in floor joist.

Inspectors can learn how air leakage from ductwork may cause home energy loss increase utility bills lower comfort levels and make the hvac system less efficient. Did that cause problems. Building cavities used as return air plenums is one of the leading causes of duct leakage in homes today. You rarely construct a plenum i have some who will call a mechanical room with a free return a plenum and that is incorrect.

It is impossible to create an airtight seal with this method and together with the negative pressure that is created inside the cavity air leakage occurs through joints of the rim at the end of the joist cavity. Corrective measures are also suggested. As a result this panned joist return duct sucked in a lot of air from this basement when the furnace or air conditioner were running. Plan your cold air return ducts to fit comfortably in this area.

For example an 8 by 14 inch rectangular duct will fit between 2 by 10 floor joists installed 16 inches apart on center. Secure the duct to the ceiling joists with 1 inch galvanized hanger strap. An enclosed portion of the building structure other than an occupiable space being conditioned that is designed to allow air movement and thereby serve as part of an air distribution system. See reference 2 for pictures of s slips and drive cleats the return air duct should be installed tight to the bottom of the ceiling joists so it makes a tight seal with the panning.