Chimney-style range hood with a glass canopy over a cooktop

Generic photo: Bilguun Gantumur · Pexels License

Cold air, odors or insects coming in through the range hood when it's off

Two dampers should block the duct when the fan is off: one at the hood and one in the wall or roof cap. Grease, bends, missing springs or screws in the path keep them open. Long duct runs and a house under negative pressure make it worse. Fix the dampers first; make-up air questions go to code and an HVAC or licensed contractor.

Cross-checked ~60 min moderateBrands: All

Before you start

Breaker off before removing the hood or duct connection
Ladder safety when reaching the exterior cap; roof work only with fall protection
Do not change gas appliance venting or make-up air ducts yourself; refer to a licensed contractor

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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