Powerful kitchen range hoods can vent 1,500 cubic feet or more of air per minute (cfm), quickly clearing the room of contaminants and cooking odors. For comparison, bath fans typically exhaust 100 cfm. But such powerful exhaust fans can also draw makeup air from unwanted sources, such as fireplaces, moldy crawl spaces, and gas heating appliances.
This depressurization with the accompanying pulling of air from undesirable places is increasingly prevalent as we construct homes to ever tighter standards. Even builders aware of the range hood depressurization problem and its associated potential health hazards have struggled for years to find a way to provide makeup air to replace the air being exhausted by the hood.
The above scenario is the backdrop for Fantech’s newly launched Makeup Air System (MUAS), a through-the-wall duct kit that balances outgoing air with an equal amount of introduced outdoor air. When the range hood is turned on, the Fantech unit opens a motorized damper, which then triggers the fan. The fan speed is automatically synchronized with the exhaust system’s fan, so the amount of makeup air matches the output of the range hood. The controller is the brains of the system. The outside air being brought in is filtered and can even be tempered with an optional heater kit when the introduced outside air is cold.