Air return outside room

Heating · Mid- and High-Efficiency Furnaces · printed page 131 (PDF page 132)

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Book index entries

Air Return – Outside Rooms Heating Distribution System – Forced Air

Text in the illustration

when the air return is outside the bedroom (e.g. in the hallway) the door should be trimmed at the bottom to permit air circulation
if the air can't circulate, the room becomes pressurized and won't warm up
heat register
trim here

Generated explanation

The illustration shows a bedroom with a floor-mounted heat register and a return-air grille outside the room, visible through the open doorway. An arrow and dashed line at the door bottom indicate where to trim the door to provide an air-transfer gap. This undercut allows air supplied to the bedroom to reach the hallway return when the door is closed. The annotation warns that without adequate circulation, the room becomes pressurized and will not warm up properly.

Components

supply-air floor register return-air grille interior door door undercut door frame window

Defects shown

Insufficient clearance beneath a bedroom door for return-air circulation Room pressurization and inadequate heating when the return-air path is restricted

Related illustrations

1258

Air return outside room

· p. 223

The illustration shows a bedroom with a floor supply register and a return-air grille outside the room, visible through the open doorway. Arrows and a dashed line at the bottom of the door indicate where to trim the door

0790

Supply air registers, diffusers and grilles

· p. 130

The illustration identifies three types of forced-air duct outlets and inlets: a grille, a register, and a diffuser. The rectangular grille has fixed parallel slats and is identified as typical for air returns and not ad