Consumer microwave ovens come in both freestanding and built-in models. When remodeling an existing kitchen or planning a new one, many homeowners install a built-in oven. Built-in microwaves free up counter space for other appliances and for food preparation, though the trade-off is that a built-in reduces available cabinet space. These microwaves are available in two configurations, over-the-range ovens and cabinet installations.

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Microwave ovens are available in a wide variety of sizes and designs.

Cabinet Size Restrictions

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Kitchen wall cabinets, right, are 12 inches deep, but an oven column, left, is deeper.

Standard kitchen cabinet dimensions have some control over the maximum dimensions of built-in microwaves, especially over-the-range models. The standard depth of wall cabinets is 12 inches, which limits the front-to-back size of an oven. Most microwaves intended for installation above a stove are 15 to 16 inches deep. A microwave installed in a lower cabinet or a cabinet designed for a wall oven can be larger front-to-rear because these cabinets are 24 inches deep.

Over-the-Range Models

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The size of an over-the-range microwave is restricted by cabinet size.

Over-the-range microwaves often incorporate lights and exhaust fans on their base. The housings for these conveniences add to the height of the appliance compared to a countertop model, so the cabinetry above the stove must be sized to allow room to work beneath the microwave. There is no standard height for these models, but most are 15 to 17 inches tall.

Choosing an Over-the-Range Microwave

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The microwave width usually matches the stove width.

The width of an over-the-range model should match the width of the stove, so standard oven widths are 30 and 36 inches. When replacing an existing microwave, be certain to match the width of the old one. Match the height of the microwave you are replacing to avoid exposing an unfinished space on the wall.

Built-in Ovens

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A built-in microwave can be paired with a wall oven.

Built-in microwaves are usually paired with a conventional oven in a 24-inch "oven column" or installed in a 24-inch base cabinet. These deeper cabinets allow the use of larger, deeper ovens. Built-in models are designed to fit standard cabinet widths, which have openings 24, 27 and 30 inches wide -- the size of standard wall ovens. Microwaves intended for built-in installation are available in heights ranging from about 19 to 22 inches.

Choosing a Built-in Microwave

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A built-in microwave installed without a trim kit.

Measure the opening height and width and the cabinet depth before shopping for a replacement built-in oven. To avoid fit problems, replace an existing built-in microwave oven with one approximately the same height and width. Trim kits are available for built-in models; face plates that allow you to install the oven in an open cabinet space and conceal any gaps between the oven and the cabinet frame.