**Install the main ductwork before the cabinets**, then mount the hood and make the final duct connection after the cabinets are installed. With the cabinets out of the way, you’ll have easier access for cutting openings, fastening the duct, and sealing joints.

The best sequence is:

1. **Choose the hood and finalize the cabinet layout.** Its installation instructions determine duct size, outlet location, and clearance above the cooking surface.
2. **Install the exterior vent and rough ductwork**, positioning the hood end to match that layout. Arrange the electrical supply at this stage too.
3. **Install the cabinets**, with any necessary duct openings.
4. **Mount and connect the hood**, then finish any soffit or enclosure above the cabinets.

For the run above your cabinets, allow enough space for the duct **and its elbows** before deciding cabinet height or crown molding. Use the specified duct size and keep the route short and straight; those details affect hood performance. [Zephyr installation guidance](https://zephyronline.com/customer-care/product-education/)

Use metal ductwork and terminate it outdoors through a suitable wall or roof cap—not in the attic. [Broan installation instructions](https://broan-nutone.com/getmedia/73c167fa-d352-4ec2-9aea-fef447dee127/Installation_Guide_BU2_1.pdf?ext=.pdf)