Can I heat this? Or, how important is microwave vent clearance?

January 15, 2021 9:25 AM

What happens if my microwave doesn't have the manufacturer's recommended clearances on each side? Will I burn down the house and die horribly?

I just moved to a new place that has a cabinet alcove in the kitchen that is clearly designed to hold a microwave -- it is 18"x 13"x13.5" and contains a hole for a power cord to go through. The smallest microwave I can find is 17.1" x 13"x 10". So far so good.

But it appears that every microwave on the market claims to need 12" of clearance above it and 3" of clearance on each side.

Does it really? What if I don't? I really want to use this alcove to free up counter space, and if the likely failure mode here is that my cheapo microwave lasts 3 years instead of 10 years, whatever, I don't care. But I also don't want to burn down the house!

posted by phoenixy to Home & Garden (5 answers total)

I've had the same microwave since 2003 ... two inches of clearance on the top, one inch on the sides and back.
posted by typetive at 9:32 AM on January 15, 2021 [1 favorite]

Obviously, the safest option is to follow mfg recommendations. HAVING SAID THAT, microwaves have safety thermal cut outs (usually one on the magnetron and one on the microwave cavity) which will shut it off if it overheats. I would look to see where the microwave vents (typically a perforated grille in the back and sometimes some louvers on the side) and make sure they aren't totally obstructed. Don't buy a microwave with grilling or convection features if you're going to cram it in a small spot. One more point- a microwave is typically used for a duty cycle of ten minutes or less with someone in the room at the time. It's not going to get hot when not in use.
posted by Larry David Syndrome at 9:43 AM on January 15, 2021 [6 favorites]

My microwave has vents on the rear and on one side, and I have a cabinet alcove similar to the one you describe; I've put a piece of wood behind the microwave so that I don't accidentally push it back too far, so it has two inches of clearances on all sides except the side without vents, which is about 1/4" off the wall. I've had the same microwave in the same cabinet for over a decade and seen no ill effects.
posted by mhoye at 10:20 AM on January 15, 2021 [1 favorite]

If it's really a concern, you could look at buying a built-in microwave rather than a stand-alone countertop model. Such models are designed to be safely installed in closed spaces like the one you're describing. Of course, the installation is a bit more complicated than the "just plug it in" installation procedure for a countertop model.
posted by Johnny Assay at 11:54 AM on January 15, 2021

I have multiple stacked containers AND my air fryer on top of my microwave permanently in the kitchen. It's fine for years. Bought that way more than five years ago. Pretty much just walked into a Best Buy and picked up a Panasonic 1200W carousel. It's been doing fine for years (air fryer added last year).
posted by kschang at 7:06 PM on January 15, 2021