HVAC systems work very similarly to how people breathe: air is taken in, the air is “conditioned,” and then the air is sent back out. In an HVAc system, main supply lines, vents, and cold air returns all play a part in this air cycle.
What is a main supply line?
After air is heated or cooled, it travels through a main supply line that eventually branches off into smaller ducts that lead to supply vents throughout the building. Most houses have one main supply line, although larger houses and buildings might have more.
What is a supply vent?
After traveling through the main supply line, cooled or warmed air enters a room through one or more supply vents. Generally they are either rectangular and located directy on the floor, directly on the ceiling, or on the wall very close to the ceiling; or they are square and located on the ceiling. If the heater or air condition is on, air will be flowing FROM these supply vents into the room.
What is a cold air return?
“Old” air is sucked from each room so that it can be heated or cooled before being recirculated. Air is sucked from the house through cold air returns. They are usually larger than vents and tend to be located at the base of the wall close to the floor. Air will not flow from these vents into the room, although it is possible to feel air leaving through them.
