What duct size for my range hood?

Use the size specified by your hood manufacturer, typically 6" for hoods under 600 CFM and 8" for larger hoods.

Rigid or semi-rigid duct is strongly recommended for kitchen exhaust to reduce grease buildup.

Range Hood Duct KitGenerating image…

HVAC & Ventilation

Exhaust Fans

Budget: $20-$40 (basic wall vent kit) | Mid-range: $40-$80 (complete kit with rigid duct) | Premium: $80-$150 (roof vent kit with flashing)

Range Hood Duct Kits: Kitchen Exhaust Venting Solutions (2026)

Prepared by Lumberama's Building Materials Team

|Last updated May 25, 2026|Sources & methodology

Range hood duct kits provide the ducting components needed to vent kitchen exhaust to the outdoors. Kits typically include rigid or semi-rigid duct, wall or roof cap, elbows, and clamps. Proper venting removes cooking grease, smoke, moisture, and odors from the kitchen.

Key Features

Complete venting kit with duct and cap; Available in 6" and 8" diameters; Wall cap or roof cap termination options; Rigid and semi-rigid duct options; Includes elbows
clamps
and connectors

Specifications

Duct diameter: 6" or 8" | Duct type: rigid aluminum or galvanized steel | Wall cap: louvered with damper | Max run: varies by hood CFM | Elbows: 90° adjustable

Applications

Venting range hoods to exterior; Kitchen exhaust systems; Over-the-range microwave venting; Downdraft cooktop venting; Kitchen remodel duct installations

Installation Overview

Plan shortest route from hood to exterior wall or roof. Cut exterior opening. Run rigid duct from hood to cap with minimal elbows. Seal all joints with foil tape. Install wall or roof cap with proper flashing.

Pros & Cons

Pros

✓ Complete kit simplifies purchasing; Rigid duct provides best airflow; Proper venting improves air quality; Removes grease and cooking odors

Cons

✗ Requires cutting exterior wall or roof; Longer runs reduce hood performance; Each elbow reduces CFM capacity; Roof venting is more complex to install

Top Brands

Broan-NuTone

Imperial

Lambro

Code Requirements

Kitchen exhaust must vent to exterior per IRC M1503. Minimum duct size per range hood manufacturer. Maximum duct run length varies by hood CFM. Makeup air may be required for hoods over 400 CFM.

Buying Tips

Measure the distance from hood to exterior before buying to ensure you have enough duct; Use rigid duct over flex for kitchen exhaust - it stays cleaner and flows better; Minimize elbows as each 90° turn reduces hood capacity by about 10%