Do Built-In Microwaves Need to Be Vented
What to know

Do Built-In Microwaves Need to Be Vented?

A built-in microwave is a microwave with nobody but has a door and a face that you’re supposed to install into your cabinet for space-saving purposes. This is in stark contrast of countertop microwaves small enough to be repurposed as built-ins with a trim kit. They retain their bodies.

With that said, how about microwave ventilation inside those cramped spaces where built-ins are put into? Let’s explore what’s the deal with built-in microwaves and ventilation.

Do Built-In Microwaves Need To Be Vented?

Built-in microwaves work better when vented or at least have ample ventilation. For Over-the-Range microwaves, they’re ventilated by default, whether they’re ducted or ductless. The microwave recirculating fan of an OTR microwave is less effective than a range fan.

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However, this is because it’s a two-in-one device—a microwave that doubles as a range fan with a 300 CFM (cubic feet per minute) ventilation fan doing the work while the rest of it is an ordinary microwave. This is in contrast with a range hood fan that is built solely for ventilation purposes.

A Built-in microwave
A Built-in microwave

Ventilation for Built-Ins vs. Over-the-Range Microwaves

As for the built-in microwave, it has parts for ventilation but it is way less effective than what the OTR microwave has. It’s about the same as the countertop, except perhaps more effective when dealing with the cramped spaces of a kitchen cabinet.

Ventilation instructions and considerations will be outlined on the manufacturer’s manual. It describes how much depth your cabinet should have to fit in your built-in microwave. Typically, it’s about 15 inches.

Do Built-In Microwaves Need to Be Vented Above the Counter?

Built-in microwaves placed above-counter or above the counter in a wall also require ventilation. Whenever you built your microwave into the cabinetry or wall, you need at least 3 inches of breathing room on all sides to save the back (about an inch away at least) and the bottom (ditto).

As mentioned above, a cabinet should be about 15 inches deep to accommodate most decent-sized built-ins. You can avail of trim kits to allow at least 1½ inches of vented space around the device. If you want a specific cabinet-wall location but the cabinets are too shallow, you can use under-cabinets instead.

The Benefits of Above-Counter Cabinets

An above-counter placement on the wall, the under-cabinet shelf, or on an elevated portion of a kitchen island is viable for built-in placement. It’s a space-saving strategy that makes the microwave easy to access and close to your eye level. You don’t need to bow or anything.

This placement also allows you quick counter space access, whether above the microwave, underneath it, or at a nearby table where the countertop is placed. As long as the cabinet is deep enough and there’s enough clearance around the built-in, ventilation is a breeze.

What are the Other Safety Clearance Measurements Microwaves Should Have?

OTR microwaves can tolerate the heat from the stovetop but even it requires a bit of clearance because all microwaves can end up damaged or overheated if directly in the line of fire of an open-fire stove or a boiling pot.

The microwave should have enough clearance to avoid the high temperatures of stoves, ovens, or any other heat source. OTRs should be placed around the same area you’d place a hood event. For countertops, it should have feet that lift it about an inch away from the surface it’s sitting above.

A microwave that lacks feet is more unstable so make sure not to tamper with its feet. Avoid placing cookbooks, small appliances, trays, and whatnot on the microwave for good measure.

Further Info on Clearances and Precautions

The front edge of the microwave from the door onwards should be at least 3 inches or more back on the counter to keep it from tipping over face-first onto the floor. That’s a few thousand dollars down the drain if you’re not careful.

Countertop microwaves should be 2-4 feet away or more from the gas range—ditto with the fridge or a sink if you’re following kitchen triangle rules. The bottom of both the countertop and the built-in should have an inch of space at the bottom, also for venting purposes.

According to the National Kitchen and Bath Association, any microwave should be 54 inches above the floor. Meanwhile, the National Kitchen and Bath Association recommends 30 inches clearance between the stove and OTR microwave.

Do Built-In Microwaves Need to Be Vented Under the Counter?

Under-the-counter microwaves need venting as well. Any microwave needs breathing space. Built-ins are typically placed under the counter to keep it out of the way for storage and to keep the small kitchen from being too crowded.

In light of this, you better make sure your under-counter has ample space of more than 3 inches all around the microwave (trim kits notwithstanding) to give it enough space for venting the same way you would with the above-counter built-in.

How Vented Are Under-Counter Microwaves?

Actually, most under-counter microwaves have plenty of breathing room since most under-counter cabinets span the whole height of the waist-level or stomach-level countertop. This should give your built-in more than 3 inches of space, whether it’s on a drawer shelf or on the under-cabinet itself.

It’s kind of like the conventional oven placed under the stovetop or your dishwasher. It has a drawer that allows you to draw the door down and place your food for microwaving. You need to bend down to access it though.

You can spare about as much space from the counter to the ceiling, but most people divide that space into two levels of cabinets. Observe clearance recommendations to avoid placing the microwave directly onto the floor (which isn’t recommended).

Things to Keep in Mind

To keep your built-in well-ventilated, it doesn’t necessarily need a duct-like OTR. Instead, your cabinet should (typically) be 15 inches deep or there’s at least 1-inch space between the wall and the back of the unit.

Additionally, there should be 3 inches of space all around it and an inch of space at the bottom. The International Residential Code recommends a 30-inch clearance between the stove and OTR microwave.

Meanwhile, it’s recommended by the National Kitchen and Bath Association that your microwave should be 54 inches above the floor (and 18 inches above the stove).

References:

  1. Evan Gillespie, “What Is the Proper Distance to Separate a Microwave & a Range Top?” Hunker.com, Retrieved August 17, 2021
  2. Meghan Drueding, “Making Room for the Microwave“, ThisOldHouse.com, August 18, 2021

Through the years, the microwave oven has become a standard appliance for all homes. It is safe to say that there is no home without a microwave oven. If you are looking for a microwave oven that best fits your needs, You find the right website.

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