Range hood ducting: duct size, route, termination and makeup air
Hood performance depends more on the duct than the blower. Use the duct size the hood requires (never smaller), smooth metal duct, as few elbows as possible, and a proper wall or roof cap with a damper. Larger hoods can trigger a makeup-air requirement under local code (commonly when the hood can exhaust more than 400 CFM in homes with certain fuel-burning appliances).
Single source ~240 min advancedBrands: All
Before you start
- Power off at the breaker before wiring the hood.
- Never terminate the duct into an attic, soffit space or wall cavity: always to the outside.
- Makeup air and any work near gas appliances: check local code and refer when required.
- Cutting exterior walls or roofs: check for wiring, plumbing and structure first.
Diagnostic steps
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