Proper Location of a Cold Air Return In-Home for a Gas Furnace

How Gas Furnaces Work

• Gas furnaces burn natural gas inside a combustion chamber that heats air. The blower for the furnace pushes warmed air from the outside of the chamber through the heating ducts in your home to warm each room with a vent. As the heated air cools, it sinks to the floor. This cold air eventually moves to the cold air return duct to be heated again.

Cold Air Return

• The cold air return system should supply your gas furnace some of the air it needs to cycle back through the house. Fresh air from outside the home is also used in the system to ensure that the furnace has enough oxygen for combustion. The cold air return ducts not only bring the cooled air from your home back to the furnace, but with the proper placement, they can improve how the heated air in your home moves.

Locations

• When you heat your home, you want the warmed air to flow across the rooms in your home. The warm air vents need to be low on the floor or wall so that the heated air rises throughout the room. Cold air return ducts should be opposite the heated air supply vents. This will help the heated air to move across the entire room before entering the cold air return. Place the return air vent low on a wall.

Where Not to Put Return Ducts

• The return air ducts should not be installed high on a wall. Cold air sinks, and if you placed the vent high on the wall, the cold air would not easily reach it. Avoid placing the return air vent inside a moist environment, such as the bathroom or kitchen. The dampness in the air will be drawn into your heating system and redistributed throughout your home, along with any odors from the bathroom or kitchen.