IF – You have a range hood rated at 400-CFM or more
AND – You have a naturally drafting piece of equipment and/or fireplace
THEN – You are required to have make-up air
Because new homes are built so airtight, large volume exhaust hoods are likely to backdraft fireplaces, boilers, hot water heaters, or any naturally drafting appliance causing flue gases and carbon monoxide to enter the building. It’s important that a source of outside air becomes available to equalize any negative pressure caused by the fan.
Option 1 –
AUTOMATIC DAMPER: The simplest method is to install an outdoor intake air duct with automatic damper, connected to the HVAC system, that opens whenever the kitchen range hood is operating.
Option 2 –
MAKE UP AIR UNIT: An inline fan brings in outside air at a rate equal to the range exhaust output. This allows for filtering and pre-heating of the incoming air. This is
effective way to ensure that the building remains at a neutral or slightly positive pressure.
Option 3 –
