What Is a Register Box for Air Conditioners?

Air Flows

• Central air conditioning systems rely on a network of supply and return registers to regulate temperatures throughout a home. Register boxes sit inside specific areas or zones to provide a balanced cooling effect. A central air conditioner operates within a closed-air system, meaning the air conditioner “reconditions” the same air over and over again. A series of ducts that run between walls and floors connect the air conditioner unit to the register box locations.

Return Registers

• As part of a central air conditioner’s closed-air system, return registers work in tandem with supply registers to move air in and out of a home’s living spaces. A home usually has one centrally located return register, though some homes may have more than one in different locations. A central location, such as a living room, provides the register with access to the air flows that move throughout the home. Return registers re-circulate “used” air through the air conditioner unit. This allows the system to remove any heat present in a home’s living area.

Supply Registers

• Within a central air conditioning system, supply registers deliver cool air to individual rooms throughout the home. Supply registers may appear in the ceiling, the wall or the floor of a room. The system uses refrigerant liquids to extract heat from the air received from a home’s return register. Once removed, the system delivers cool reconditioned air throughout the home. Some supply registers include a lever that opens and closes the register, which allows for increased or reduced air flows within a room.

Effects

• Register boxes make it possible for central air conditioning systems to balance the delivery of air flow within a home based on the desired thermostat settings. When an air conditioner system shows a reduction in cooling capacity in certain areas of a home, problems may originate in the register boxes, or in the ductwork leading to the registers. Crimped or crushed ductwork lines can impede air flow to supply registers or from return registers. Some register boxes also include air filters that prevent dust and debris from entering the air conditioning system. Old or dirty air filters can also impede air flow through the system.