Replacing a Microwave With a Range Hood: Swap Guide

Over-the-range microwaves promise to save counter space, but most of them are weak ventilators that pull only a fraction of the smoke and grease a real hood captures. Replacing a microwave with a range hood fixes that, and it usually takes an afternoon rather than a remodel. The work comes down to four things: dealing with the tall gap the microwave leaves behind, connecting the hood to the existing duct and damper, finishing the cabinet bottom so it looks intentional, and sorting out the outlet that used to feed the microwave.

Part of our Kitchen Remodeling guide — explore the full guide →

If your microwave already vented outdoors through the wall or roof, you are in good shape, because the ductwork is already there. If it recirculated air back into the kitchen, you can still install a hood, either a ductless model with charcoal filters or a ducted one if you are willing to run new ductwork.

Before you start, measure the space. Most over-the-range microwaves are 30 inches wide and about 16 to 18 inches tall, while a typical under cabinet range hood is 5 to 8 inches tall. That leaves a gap of roughly 10 inches between the hood and the bottom of the cabinet, which is the main design problem to solve.

Planning for Replacing a Microwave With a Range Hood

Start with the manufacturer’s height requirement. Most hoods should sit about 24 to 30 inches above the cooktop for a gas range and roughly 20 to 30 inches above an electric one; the hood’s manual sets the exact range. Microwaves often hang only about 13 to 16 inches above the burners, so simply bolting a hood to the same cabinet puts it in the right range once you account for the height difference.

Next, check the ducting. Look inside the cabinet above the microwave. A round or rectangular duct running up through the cabinet, or a wall cap on the exterior behind the microwave, means it was ducted outdoors. Note the duct size: many microwaves use a 3-1/4 by 10-inch rectangular duct, while many hoods need a 6-inch or 7-inch round duct. A transition fitting often bridges the difference, but a larger hood may need the duct upsized to meet its airflow rating.

Finally, look at the power. Microwaves plug into a receptacle inside the upper cabinet. Hoods may plug in or be hardwired, depending on the model. Knowing which one you are buying lets you plan the electrical side before the old unit comes down.

Tools and Materials

• New range hood, ducted or ductless, at least as wide as the cooktop
• Duct transition, foil tape and a backdraft damper if the existing one is worn
• Filler material: a matching cabinet panel, a short wall cabinet, or a hood liner/insert
• Non-contact voltage tester, screwdrivers and a drill
• Stud finder, level and tape measure
• Stepladder rated for your weight plus tools
• A helper for lifting

Step-by-Step Swap

1. Turn off the power. Unplug the microwave if you can reach the plug, then turn off the breaker for that circuit and confirm the receptacle is dead with a non-contact voltage tester.
2. Remove the microwave. With a helper supporting the unit, remove the bolts that pass through the cabinet bottom, tilt the microwave forward off the wall plate, and lower it. Then unscrew the wall mounting plate.
3. Inspect the duct and damper. Check the exterior damper flap swings freely and closes fully. A stuck or broken damper lets cold air and insects in, so replace it now if needed.
4. Fill the gap. Pick a filler approach (a lowered cabinet, a short box or a hood liner) and install it before the hood goes up.
5. Prepare the hood. Remove the knockout that matches your duct direction (top or rear), attach the damper collar and, if ductless, install the recirculating kit.
6. Mount the hood. Hold it in position, mark screw locations, drill pilot holes and fasten it to the cabinet bottom or the filler with the supplied screws. Check level before tightening fully.
7. Connect the duct. Join the hood collar to the existing duct with a transition as needed and seal every seam with foil tape. Avoid plain cloth duct tape, which fails with heat.
8. Connect power and test. Plug in or have the hood wired, restore the breaker, then test every fan speed and the lights.

Filling the Gap Above the Hood

This is where the job either looks built-in or looks like a microwave went missing. Here are the most common solutions:

Lower the existing cabinet

If the cabinet above the microwave is a standard wall cabinet, you can remove it and remount it lower, or replace it with a taller cabinet. That puts storage where the gap was and places the hood at the right height.

Add a short cabinet or box

A 12-inch-tall wall cabinet, or a simple plywood box faced with a matching panel, fills the space and hides the duct. Paint or veneer it to match the rest of the kitchen.

Use a hood liner or insert

A decorative wood or panel surround with an insert blower creates a custom look. It costs more but turns the swap into a focal point.

Whichever you pick, make sure the bottom of the cabinet or box is flat, solid and able to hold the hood’s weight. Most hoods weigh 15 to 40 pounds; secure the filler into studs or the cabinet frame, not just drywall.

Electrical Considerations

The microwave outlet often sits inside the upper cabinet on a dedicated 20-amp circuit. Many plug-in hoods can use that receptacle directly, which is the simplest path. For a hardwired hood, the receptacle has to be replaced with a junction box and the hood wired in, and some hoods require the connection to be made inside the hood’s own wiring compartment.

Always turn off the breaker and confirm power is off with a non-contact voltage tester before touching any wiring. Relocating the outlet, adding a new box, or converting a receptacle to hardwired service is best left to a licensed electrician if you have any doubt, and local rules may require a permit. A hood blower is line-voltage equipment, not low-voltage like some under-cabinet lights, so treat it with the same care as any 120-volt appliance.

Ladder and Lifting Safety

Microwaves often weigh 50 to 65 pounds and sit at shoulder height, which is an awkward combination. Use a stable stepladder on a clean floor, never stand on the countertop or range, and keep your hips between the ladder rails. Have a helper take the weight while you remove bolts. Lifting a hood into place is easier, but the same rule applies: support the unit before fastening, not after.

Troubleshooting After the Swap

The hood is loud but pulls little air

Usually the duct is undersized or there is a restriction. A rectangular microwave duct can choke a higher-capacity hood. Upsizing the duct or reducing elbows helps.

Cold drafts or rattling

The exterior damper is not closing. Clear debris or replace the wall cap.

Grease drips on the cooktop

Filters need cleaning. Most mesh or baffle filters go in the dishwasher monthly with heavy cooking.

Cost and When to Call a Pro

A basic ducted hood that reuses an existing outlet and duct is inexpensive compared with a new microwave. Filling the gap with a matching cabinet or custom box adds materials and a bit of carpentry, while a decorative hood liner can cost significantly more. Professional installation of a hood swap typically runs a few hundred dollars, and more if duct or wiring changes are needed.

Call a pro when the duct needs upsizing through a wall or roof, when the hood must be hardwired or the outlet relocated, or when cabinets need to be rebuilt to match. An electrician handles the wiring, and a contractor or cabinet installer handles duct and carpentry. For many kitchens, though, replacing a microwave with a range hood is a manageable DIY project that dramatically improves ventilation. Many homeowners who install microwave hood combos later wish they had gone with a dedicated hood from the start.