How To Install a Microwave Hood with Exhaust Fan

Installing a microwave hood with an exhaust fan is a practical way to save counter space in your kitchen and improve the area’s ventilation. This appliance combines the convenience of a microwave with the functionality of a range hood, which makes it practical for any homeowner or cooking enthusiast. Read our step-by-step guide below, and watch the video above for tips from This Old House general contractor Tom Silva.

Preparing for Microwave Hood Installation

Gather the necessary tools and materials before you begin installation, and make sure you’ve prepared your space.

Tools and Materials Needed

You’ll need the tools and materials below to install a microwave hood with an exhaust fan: 

• Angle grinder
• Caulk gun
• Circular saw
• Drill/driver
• Level
• Measuring tape
• Oscillating multi-tool
• Reciprocating saw
• Safety glasses and work gloves
• Screwdriver set
• Stud finder

Pre-Installation Considerations

Consider the factors below before you start installation: 

• Determine whether you’ll vent the exhaust fan through an exterior wall or up through the roof.
• Make sure you abide by any local building codes.
• Make sure your kitchen has the appropriate electrical outlet for the microwave.
• Verify that the microwave hood will fit in the space above your range.

Marking and Cutting the Wall for a Microwave Hood

Start the installation project by marking and cutting the appropriate openings in the wall.

Using the Manufacturer’s Template

Follow the steps below to properly use the manufacturer’s template: 

1. Locate the manufacturer’s template that comes with your microwave hood.
2. Position the template on the wall above your range and center it. Make sure it’s level. 
3. Use a pencil to trace the cutout lines onto the wall.

Cutting the Drywall

Once you’ve marked the wall, you can begin cutting drywall. Follow the steps below.

1. Put on your safety glasses and work gloves.
2. Use an oscillating multi-tool to carefully cut along the marked lines.
3. Remove the cut section of drywall and any insulation behind it.

Framing the Opening to Support the Microwave Hood

After you’ve cut the initial opening, you may need to reframe the area to properly support the microwave hood. 

Removing Obstructions

Follow the steps below if you encounter a wall stud that’s in the way of your exhaust vent:

1. Enlarge the hole in the drywall around the stud.
2. Use the oscillating multi-tool to cut out the section of the stud that’s in the way.

Installing New Framing

Follow the steps below to sufficiently support your microwave hood:

1. Cut two-by-fours to create a bottom plate, header, and jack studs.
2. Install the new framing pieces, and secure them to the existing framing with 3-inch screws.
3. Fill any voids along the new framing with fiberglass insulation.

Preparing the Microwave Hood Mounting Surface

You must have a solid mounting surface to successfully complete your installation. Follow the steps below to prepare the wall for the weight of the microwave hood.

Installing a Plywood Panel

Install a plywood panel by following the steps below. 

1. Cut a piece of 1/2-inch plywood so that it fits over the newly framed opening.
2. Mark and cut out the exhaust opening in the plywood.
3. Secure the plywood panel to the framing with screws.

Mounting the Bracket

Next, mount the bracket by following the steps below. 

1. Locate the mounting bracket that came with your microwave hood.
2. Position the bracket on the plywood panel so that it’s centered. Make sure it’s level.
3. Secure the bracket to the plywood and framing with screws.

Creating the Exterior Vent Opening for the Hood

You must create an opening in the exterior wall to allow for proper ventilation. A successful vent opening effectively removes cooking fumes and smoke from the kitchen.

Marking the Exterior Wall

Mark the exterior wall by drilling small pilot holes at each corner of the exhaust opening from the inside. These holes will guide you when you begin cutting from the outside.

Cutting the Exterior Opening

Follow the steps below to cut the exterior opening:

1. Use an angle grinder or oscillating multi-tool to carefully cut through the siding along your marked lines.
2. Switch to a reciprocating saw to cut through the plywood sheathing.
3. Make sure the opening is clean and matches the size of your vent hood.

Installing the Microwave Hood

Once you’ve completed the preparatory work, you can install the microwave hood. When you’re done, the appliance will finally be in place. 

Positioning the Microwave

Follow the steps below to position the microwave: 

1. Lift the microwave hood and carefully position it on the mounting bracket.
2. Make sure the tabs on the bottom of the bracket slide into slots on the back of the microwave.
3. Gently tilt the microwave upward and feed the power cord through the hole in the cabinet above.

Securing the Microwave

Follow the steps below to secure the microwave: 

1. Once you’ve set the microwave in place, open the door to access the mounting holes.
2. Install screws through the top of the microwave into the cabinet above.
3. Tighten these screws securely to prevent the microwave from tipping forward.

Installing the Exterior Vent Hood

The final step in the project is to install the exterior vent hood to complete the exhaust system.

Preparing the Vent Hood

First, prep the vent hood. Apply a bead of silicone caulk around the perimeter of the vent hood’s flange. This will create a watertight seal.

Securing the Vent Hood

Now, secure the vent hood by following the steps below. 

1. Slide the vent hood into the opening you created from the outside.
2. Make sure it aligns with the microwave’s exhaust port.
3. Secure the vent hood to the exterior wall with screws.

Applying Insulation and Caulk

Here’s how to apply the insulation and caulk: 

1. Pack some insulation around the vent opening. This will seal any gaps and make your system more energy efficient.
2. Once you’ve put the insulation in place, apply caulk around the edges of the vent hood from the inside to create a snug fit.

Finalizing the Installation

Finish the installation by following the steps below.

1. Make sure you’ve securely mounted the microwave hood and that all screws are tight.
2. Make sure you’ve properly aligned and sealed the exterior vent hood.
3. Plug in the microwave and test the exhaust fan to make sure everything works correctly.