Supply air ducts and return air ducts are two separate halves that make up the whole of your heating and cooling air distribution system. The supply side delivers heated or cooled air from your furnace or A/C into each room through supply air vents. Return air ducts draw air out of each room through a separate air vent and convey it back to the central unit to be reheated or cooled. The entire air distribution system is a closed loop, continuously recirculating the same volume of air throughout the house.
Return air ducts are typically sheet metal and rectangular in shape. In addition to “returning” air to the furnace or air conditioner, the return ductwork also incorporates the system air filter critical to good indoor air quality.
Return ductwork is carefully sized to match the capacity of the supply ductwork. The goal is to ensure that the returns remove the same amount of air as the supply ducts deliver, maintaining neutral air balance in each room. This is the optimal condition for efficient heating and cooling. Sometimes, however, that balance is upset:
- Leaky return ducts tend to pull outside air into the ductwork versus leaking air out. This adds extra air volume to the system, tipping air balance in the house from neutral to positive. Under positive pressure, conditioned air is pushed out of the house through tiny structural cracks and gaps, resulting in higher operating costs to maintain comfortable temperatures. Your HVAC contractor can test your ductwork for leakage and suggest duct sealing options.
- In houses with a single central return vent in a hallway instead of dedicated return vents in every room, air from supply vents may not have a clear path back to the central return. Air pass-through vents should be installed in bedroom doors, or jumper ducts routed through the ceiling to pass air from room to room, in order to ensure that supply air is conveyed back to the central return vent.
For repair or maintenance of your return air ducts, contact the HVAC pros at Hansberger Refrigeration and Electric Company.
Our goal is to help educate our customers in Yuma, Arizona about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, download our free Home Comfort Guide or call us at 928-723-3183.
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