Why are you using an OTR MW at all get a proper hood that actually vents to the outside since you have the ability to do so. OTR MW are not a good idea even when not vented.You need to post pics of this vent above the front door it makes no sense to me

"I would like the OTR microwave to be flush with the 15" cabinet above."

If you check the specs for most OTR microwave ovens, you will see that the maximum cabinet depth above is 13". This Whirlpool allows 14". These appliances are not designed to be mounted flush and by protruding from the cabinet they function better as a hood for the stove.

"above the front door"

She means the oven door which is on the front of the appliance.

Get a real hood.

Patricia and Celadon i appreciate your input but i am not interested in a hood fan. I have read the pros and cons including comments on this site. The OTR microwave works for me.

Here is a picture of my kitchen. Notice how this current microwave (now broken) is shown flush with the upper 15" deep cabinet. Before, microwaves vented out of the front so this wasn't an issue regardless where your microwave vented out.

At the end of the day in my case, though, the microwave shown below doesn't vent through the front above the door and the new microwave will not vent through the front above the door. either. So is the front vent used by the microwave in any other way that would require it free and clear of the bottom of my cabinet? Maybe this is an HVAC question.

wdccruise yes i have read that too but i feel like it's a general depth requirement IN CASE you want to vent the microwave in the front. Then i agree you would need that space but in my case what purpose does the upper front vent serve?

An OTR cannot vent straight back. The plenum and duct connection is on the top. Only a specialty hood designed to vent straight out the rear can be used in the configuration that you describe. Unless you want to redo a bunch of ducting to go up and out. Or up and 90 out. And the siding and hvac work that go with that.

Get a hood.

B K I am with you. I have an OTR microwave. Do not ever want a hood. My step-son installed ours and it is vented at the top. Your instructions will tell you how and where it needs to be vented as apple pie order posted.

Celadon i'm not sure what you're talking about the vast majority of OTR microwaves have 3 options for venting. Front which doesn't really vent and recirculates back into your kitchen, back behind the microwave and top of microwave behind the back. Both of the latter two vent to outside your home.

This is one of many microwaves that can vent three different ways. https://www.whirlpool.com/kitchen/cooking/microwaves/over-the-range/p.1.7-cu.-ft.-microwave-hood-combination-with-electronic-touch-controls.wmh31017hs.html

"So is the front vent used by the microwave in any other way that would require it free and clear of the bottom of my cabinet?"

I just check-tested and can confirm that the vents at the top-front of the my GE JNM3163 microwave are used by the fan for both exhaust and intake. The installation instructions for Frigidaire OTR microwaves state, "If the cabinet depth including the cabinet doors is more than 13" then the unit must be spaced out from wall...to allow proper top vent air exhaust / intake."

I have the exact same dilemma. Why have so manufacturers stopped making otr microwaves with front facing grille vents. There are so few. Here's one I'm considering.

https://shop.sharpusa.com/1-5-cu-ft-1000w-sharp-stainless-steel-over-the-range-carousel-microwave-oven-r1514ty/

@M Coviello: As shown in figure 1 of the installation instructions, the Sharp R1514TY is to be installed in a cabinet 12" deep.

thank you @wdccruise Do you know of any otr's designed for a 15" cabinet above?

If you want to install a microwave oven in a 15"-deep cabinet, you'll need a bump-out kit. See note on this GE JNM3163 specification sheet, for example.

Thank you for this. Do you know if this kit can be used for non-GE microwaves or if it's universal. I'll research this as an option.

Upon looking closer, this would bump out Microwave well beyond the upper cabinet. Are there any options to allow a unit to be flush with the upper 15" cabinet if/when the unit is exhausted externally?

"Are there any options to allow a unit to be flush with the upper 15" cabinet..."

They can't be installed flush because the door would be blocked from swinging open on the hinge side. The oven has to extend beyond the surface of the adjacent cabinets.

Here is what my current (broken) microwave looks like. I'm basically looking for the identical setup by cannot find an OTR with the vents on the front. the side cabinets are 12" deep and above the Microwave is a 15" cabinet.

Fix the one you have.

I wish that were an option, I've looked high and low but the parts are discontinued and no longer available. This configuration although not the typical 12" upper, seems to be common enough where there should be a mfr to have an option. I still don't understand why so many mfr's used to have models like this; Now they don't. Seems like they fell out of popularity. Thanks for helping me. I'll end up finding one with front vents and exhaust externally to the back too.

"I still don't understand why so many mfr's used to have models like this..."

• Ovens have been standardized to attach to a 12" cabinet, reducing the number of appliance variations needed thereby enhancing production economies of scale.
• The removal of vents on the front of the oven allows for the door to extend to the top of the oven, providing a sleeker appearance.
• The space at the top-front of the oven was available so why not expel the air there?
• Air is expelled upward, not into the user's face.
• Moving the vents from the front to the top of the oven may have allowed the oven's interior to be made larger.