• 1 per 1000 sq-ft of crawl space units required Includes: (1) make-up air damper with air flow adjustment slide, mounting template and 6 in intake hood

The Make-Up Air System is a pressure activated activated damper that opens whenever the central fan is on or when the home becomes depressurized. While an integrated system is the recommended choice for fresh air ventilation, low-cost, secondary options include an exhaust system and/or a make-up air system. Exhaust ventilation systems remove air from a particular location, often leading to depressurization in the home. Replacement or make-up air will infiltrate through leaks in the building shell and other uncontrolled sources. A make-up air damper can be added to the central system when exhaust ventilation is employed. The MAS provides replacement air as needed from a controlled source into the return air plenum where it is tempered and distributed throughout the home. Functions with or without the HHSC+.