Every home (new and old) needs ventilation to bring in fresh air, to remove stale air, and provide moisture control.
Adding fresh air to a heating or cooling system accomplishes two primary indoor air quality goals: It pressurizes a building, and increases indoor air quality by diluting polluted or stale indoor air. Adding a fresh air inlet to most systems is typically a simple and relatively inexpensive proposition.
Outside air enters the system through a roof or sidewall vent inlet that collects air from a clean outside location. The air is pulled into the system through a filter, and then a duct connected to the return plenum. Smaller systems usually use the suction side of the air handler fan to pull in the outside air. The air mixes with the return air, and then is dispersed evenly throughout the building through the supply duct system.
***IT IS IMPORTANT*** Traditionally
when negative pressure is created through varies chimneys, fresh air is
drawn in through various cracks and crevices (windows, doors, etc) in
your home. The result is dirty, dusty, and unfiltered air pouring into
your home. Using a fresh-air return system, you control the path the air
takes buy offering a lower restriction intake that is filtered and
clean.
Filter 10 x 10 x 1 "is included in the set.