Makeup Air Damper (MUA)

Category: infrastructure

An automated mechanical ventilation intake component required when high-output range hoods exhaust large volumes of air.

International Residential Code (IRC) mandates a makeup air system whenever a range hood exhausts greater than 400 CFM (Cubic Feet per Minute). High-velocity hoods create a dangerous back-draft vacuum inside tight homes; the MUA opens an automated damper valve to pull fresh outdoor air back in.

Common Examples

• Installing a commercial-grade 1200 CFM pro-range hood required us to integrate a synchronized makeup air damper into the main HVAC ducting.
• Failing to provide mechanical makeup air can pull lethal carbon monoxide exhaust vapors backward straight out of the gas water heater flue.