Air Heating Systems - What are the Air Return Ducts?

Air Heating Systems. Integral Part.

An air return duct typically is an integral part of any heating, ventilating and air conditioning (HVAC) system. Generally, HVAC systems are a forced air process which blows either heat or air conditioning through ductwork into a home or business. An air return duct usually is located either in a hallway or in the ceiling, and its purpose is to extract air from a room and recycle it through the system to further condition it by cooling or heating.

Water Heating Systems - Air flow Means.

Most central air and heat systems have a condenser that is outdoors and a coil that is located indoors that allows one unit to both heat and cool a building. In the summer, the air return duct removes warm air from inside and transports it to the outside through ductwork to be conditioned. Ductwork is a sealed system that usually is located in the attic for structures with slabs or under the floors on structures that are raised off the ground. The purpose of a duct system is to give air a medium through which it can flow to reach the outdoor components, undergo the conditioning process, and return to the building. Once back in the building, the air usually is distributed by a fan through registers into the rooms.

Air Heat Pumps - Using Refrigerant.

HVAC systems typically use a refrigerant to cool the air by carrying the heat outside to the condenser. The compressor in the outside unit compresses the refrigerant into a high-pressure gas. Once the gas travels through the coil outdoors, it loses heat and transforms into a liquid. It then enters the evaporator coil and expands into a low-temperature gas to absorb heat that enters into the system from the air return duct. This process repeats itself until the temperature that is set on the thermostat is reached.

Air Heating Systems Home - Sealing System.

The importance of a sealed HVAC duct system can be attributed to the temperature of the air that is extracted by the air return duct. For example, for cooling purposes warmer air rises to the ceiling and colder air remains closer to the floor. The air return duct provides circulation of cold air as it pulls the cooler air upward, passing through the warm air that is closer to the ceiling. If there is a leak in the ductwork in any portion of the system, it could pull in unconditioned air, which will take more time and electricity to effectively condition. This usually causes the HVAC system to run longer and use more electricity to achieve the desired temperature.