Vent diffusers disperse pressurized air exiting heating ventilation and air conditioning (HVAC) ductwork and provide a decorative finish over the grill box hole holding the ductwork in place. Without an air diffuser, the air exiting the HVAC system would travel in a straight direction. This causes a concentration of conditioned air in one section of the room while the rest of the room remains unconditioned. The direction that a vent diffuser sends flowing air depends on the direction of the diffuser fins.
Air diffusers with stationary fins come in one-, two-, three- or four-way blows. The amount of blows that an air register uses depends on its location in relation to walls or other obstructions. A one-way blow vent diffuser has one direction to move air. This is a common air register found in directing air flow through an HVAC exhaust system.
Four-way blow vent diffusers sit in the center of rooms and disperse air across a large area of the room. Movable vent fins allow the air flow direction to change as needed. Another factor in vent diffuser selection involves the finish of the diffuser flanges and fins.
Commonly white, vent diffusers can vary in finish and material to either blend into the area surrounding the diffuser or contrast with the surrounding area to provide a unique look for a room. Brass- and copper-clad vent diffusers provide a contrast to wall, floor and ceiling finishes while matching the décor of early Victorian style homes. This allows for the comfort of central air conditioning without looking out of place in historic homes. Another option for home vent diffusers hides neatly out of sight.
Linear diffusers use a long, slim opening to disperse air from an HVAC system. The narrow opening reduces the visibility of the vent cover, allowing it to blend into the surrounding area. Typically, linear vent diffusers sit along the edges of walls or above door and window openings. After they have been installed, they are unnoticeable from a distance and provide a clean look to both historic and industrial-style homes.
Regardless of the type and style of a vent diffuser, the diffuser location has the greatest impact on the efficiency of an HVAC system. Placing a four-way blow diffuser in a location where two blows face walls will cause the air to deflect and remain stuck in one corner of a room. Pre-planning the location and type of each vent diffuser before purchasing ensures that each room of a house remains comfortable.