How Air Flows Within A Home

Ductwork is the mechanical system that distributes air through all rooms of your home.  The steps listed below will give you a basic understanding of how your ventilation system works.

1. Your furnace / air conditioner turns on to temper the air to the desired temperature set at your thermostat.
2. Air enters the supply trunk line (the large rectangular metal box that extends overhead across your basement or crawlspace).   Much like a tree trunk, the supply trunk line is the main distribution for airflow, attached to the trunk line are numerous of smaller ventilation lines called  supply lines.
3. Supply lines enter the numerous rooms within a home distributing the conditioned are through air vent registers.
4. Air flow circulates within each room to temper the air to the desired temperature.
5. Air is drawn from each room into return air vent registers (the larger vent registers typically located on the walls) to return lines, which attach to a return trunk line.
6. The return trunk line returns the air to the furnace / air conditioner filter.
7. The filter removes contaminants  from the air, and is drawn into  furnace / air conditioner.

This cycle of airflow continues until the temperature of air reaches the set temperature of the thermostat.