Blondelle, there's a little discussion towards the end of this thread:

https://www.houzz.com/discussions/is-there-a-small-over-the-range-microwave-dsvw-vd~2696070?n=195

The whirlpools are basically the same unit with different trim, I think.

The whirlpool is basically the same, but is only 400cfm.

Read almost the whole long discussion though. Was hoping someone who actually had one would comment.

Start from the end. There are several people who have one and I had specifically asked one of them about the venting.

ETA Spoiler alert: the answer was, essentially, "slightly better than a regular microwave, but not hugely."

Whirlpool/ KitchenAid/JennAir /Maytag are the same company. No one needs “extra” features in a MW. They don’t get used. If you can’t vent extetnally, forget spending a bunch of money for that at all.

"Was hoping someone who actually had one would comment."

It doesn't matter if you actually "have one". There are the laws of physics to address. And, I did have a Dacor OTR MW that I hated and switched out for a hood. It vented to the outside, but was still a poor performer because of the nature of the construction of an OTR MW. Regardless of the brand, the laws of physics are that you cannot pull much air through the tiny mesh squares on the bottom of the microwave, and that when you try to pull air like that, with no place for it to exit, the noise will be enormous. Furthermore, if there is no place for the air to exit, because the OTR MW is recirculating, the air will literally blow right back into the kitchen. Where do you think the exhausted smoke and grease will go? In addition, when you try to combine two machines into one, i.e. a microwave and a hood, there will be compromises in the functionality of both.

Also note that almost all MWs are made by Sharp and Panasonic, and when you see other band names, they are re-badges of those two manufacturers. That KA MW is not made by KA/Whirlpool.

"Wonder if the added cfm help clear the grease and smoke better."

"With all this "help" I still really haven't gotten my question answered"

Your question was answered. The answer is no, the added cfm of a recirculating microhood will not clear the grease and smoke better. It appears you wanted to hear "yes, the 500 cfms make the recirculating exhaust better". But it doesn't. So you keep saying no one is answering your question.

If you want this OTR MW because you like its profile and features, and you want the MW in the spot over the range, then get it. But it won't exhaust better than another recirculating microhood. And it will be very loud. That is the truth.

My answer to your question about whether the ventilation is adequate for this particular KA OTR MW was that it doesn't matter whether anyone has that specific unit or not. I gave the reasons why. That specific model does not change those reasons. The answer is still that a recirculating exhaust microhood at 500 cfms will not exhaust well, regardless if it's made by Sharp or Panasonic (as mentioned above, KA does not make OTR MWs).

You did not answer my question above, "since there is no place for the air to exit, where do you think the exhausted smoke and grease will go?"

Perhaps someone will post here that they find the KA OTR MW exhaust to be adequate, and then you'll be satisfied that you received an answer.

blondelle, can you share your technique that doesn't smoke up the kitchen? Can't use my grill for a while and want to cook a steak every now and then. Thanks.

Sorry I can't add anything about the microwave/venting.

Stop calling it ventilation. Recirculating doesn’t have anything to do with ventilation. It just blows all the yuck back in your face. At 500 CFM. It’s the opposite of ventilation.

"If you want this OTR MW because you like its profile and features, and you want the MW in the spot over the range, then get it. But it won't exhaust better than another recirculating microhood. And it will be very loud."

^^^Yeah, that's the long and short of it. Here's the thing. What does the word "recirculating" mean? According to the dictionary, "circulate" means "to move in a circle, circuit, or orbit; especially : to follow a course that returns to the starting point." And "recirculate" means "to circulate or cause to circulate again". So once your exhaust is a recirculating one, whether it's via a microwave or hood, well, the exhausted stuff isn't going anywhere. The 500 cfms is making it go nowhere faster than 300 cfms, and louder. I like the slim profile though. That's a really good feature to have.

KA calls it ventilation because they are assuming the homeowner will vent to the outside. If you opt to make it a recirculating exhaust, which is done by closing the MW's opening that would ordinarily connect to an exhaust duct, KA calls it a recirculating fan, not a ventilating fan. It will recirculate the exhausted air, not ventilate it.

Thanks for the clarification. Don't have too many choices here. Read lots of reviews since and didn't find one that said it didn't take stuff out of the air. 24 stories up in a Manhattan highrise windowless 50 sf. kitchen and no where to vent to. This is the best solution for me. May not have a nice big kitchen but it has what I need. Can lie in bed and see the Manhattan skyline all lit up at night from a huge window so that makes up for it.

I can't really add much to this conversation except that the only KD that I considered ever working with was someone in the industry for over 20 years, he is certified by the KBA and teaches kitchen/bath and interior design at the local community college. Very, very well respected. He showed me pictures of his new home and his new kitchen. He had an OTR microwave and I expressed my amazement (and perhaps snobbery) because I said "I can't believe you have one of those." He kicked my butt and explained that sometimes you gotta do what you gotta do.

A fantastic skyline with a home you can afford in one of the most desirable cities in the world is priceless. I spent one year in NYC after college unable to find even a couch to sleep on. Ended up in a women's dormitory in the Village run by the Salvation Army. Would make a great short story if I was a better writer. NYC is unique. Sometimes you gotta do what you gotta do.

I'll add my 2 cents here if I can. I used to have a suburban house that I did a full blown gut kitchen renovation on. A couple of permits and off we went. Pulled down the ceiling, installed duct-work through a dedicated exhaust in the roof. Beautiful range hood. Worked great. Fast forward a few years. Tired of living in the suburbs. Move to NYC. 1929 Co-Op building. Empire State Building views from the kitchen. Priceless. HOWEVER, No outside vent from the kitchen (Window excepting). Can't punch a hole to the outside. Currently have a Viking combo microwave/convection OTR. I like to cook steaks and chops. I got a 15$ box fan from Rite-Aid for the kitchen window. That helps. But actually the re-circulating loud as sin 2 speed fan in the Viking does do something. It does cut down on smoke. If I don't use it, all my smoke detectors start wailing. My old Viking is on it's last legs, so I may try one of these new compact OTRs.

So.. can we all agree to try to understand our different kitchen ventilation / re-circulation circumstances before we get all huffy about it?

My window fan does work somewhat, but it also depends on the wind direction. Sometimes it blows the wrong way and no amount of fan action will help. Also, the fan gets really greasy. The screen in the window gets nasty, too. I see how restaurants can have grease fires unless they clean things religiously.

Ok, got the Kitchen Aide KMLS311HSS , the price is now $550.00. Installed it myself, not too difficult, needed an extra strong person to mount it. Looks good, the recirculating fan does a much better job of controlling smoke than the old Viking. Quieter, too. The 2 level LED lights much better than the old

. My wife is 5' 5" and she can juuuust reach high enough to operate things. Overall very happy.

Too bad about the Ikea cabinets. I imagine that KA is being overly cautious with the venting requirements. Here is a top shot...

I measure 13 3/4" deep from back wall to cabinet front. So 14" would be OK. There are no vents on either side of the unit, only the ones on top.

What a great looking microwave! Does this come in a convection version as well?

That top venting in front of the cabinet doors- do you think there is a concern for the doors? What blows out there? Mine will be 14” deep, and seeing that, I’m wondering if 12” would have been better.

We just installed the Whirlpool version with our IKEA cabinets. Had to bump it out about 1.5 inches for the upper vents to clear the cabinet doors. It sticks out pretty far, but I'd rather have it 2 inches farther out and 6 inches higher up then right in my face, so I'm fine with the trade-off. Haven't tested its fan capabilities yet because our kitchen is still being put back together, but I'm 5'2" and can reach it well enough, and it looks fine.

No convection. If it did that, it would be a lot bigger.

Philip, did you try using it to cook a steak? Is the kitchen still smokey? Is there a lot of grease on the cabinet doors above it? Thanks!

Swordfish tonight. Will let you know how the smell/smoke is handled.

Swordfish was tasty. Considering how much smoke was pouring off the pan, the recirculating system did a good job. Super hot cast iron pan and sugary peach sauce. The apartment smells like swordfish, but that is to be expected even with a vented exhaust system.

Not sure if anyone is interested, but I bought the KA low profile and my son bought the Whirlpool. He wishes he spent the extra money for the KA after using mine because he likes the mechanical outer buttons much better, the light is better, the fan is a little stronger, and it looks nicer. FYI--both vent fans are loud (nothing Whisper Quiet about it) but they vent well. The low settings are not low enough to reduce the noise much. This is one thing I think KA/Whirlpool messed up as it seems the 4 fan speeds are like 75%, 85%, 95%, and 100%. They need to recalibrate their speeds to get some lower speed options. That said, we both love these microwaves, and neither of us would have bought a standard OTR microwave. We're building a new house and I will buy it again (and hope they recalibrate the fan speeds by that time).

A major point raised often w.r.t. hoods but missing from this OTR microwave oven topic is blower performance vs. blower rating. Blowers are generally rated by the air flow that they can induce when hanging in free space. This is the zero static pressure volumetric flow rate (CFM). When one reads the rating of a Broan/Best/Abbaka/Fantech/etc. blower, this is the number given.

In use with other equipment, whether hood, hood filters, duct, etc., or microwave oven passages, filters, duct or not, etc., the achieved volumetric flow rate is significantly lower. Blower manufacturers such as those listed above will provide graphs or tables of the effect of back pressure (pressure loss in HVAC terms) on achieved flow rate.

Whereas a hood system can be built so that the filters (preferably baffles for the higher end units) are the dominant restriction, microwave ovens filters, particularly those used for recirculation, cause much more pressure loss for a given flow rate, and this is exacerbated by the narrow passages the air may have to flow through to get around the oven.

As a result, unless the manufacturer actually specifies the flow rate of the microwave oven blower system when in place, one should hope that the resulting CFM is above 100 typical, and maybe approaching 200 for the 500 CFM rated devices. These rates over the plume expansion area at the OTR height are generally inadequate.

While not a fan of VaH due to their years of claiming magic performance, their recirculating hood has been reported on here as providing good results. While the initial cost may be highish, I recall a discussion of what the actual consumables costs were over time. The link below is the one with this discussion, as I recall.

https://www.houzz.com/discussions/2347276/vent-a-hood-ductless-ars-range-hood-update#n=65

Kaseki, you are correct. For me, the KA marketing bullet indicating "500 CFM MOTOR CLASS" was a signal that this was only the motor, and not necessarily the performance of the unit. I originally set out looking for a range hood for our new gas stove, and found myself looking for higher and higher CFM's. But further research indicated numerous flaws with this approach such as determining my true ventilation needs, verification of performance ratings for the hood as a unit, electrical requirements, noise, and perhaps most importantly--the need for make-up air (by code) in some homes. I rely on Green Building Advisor for such questions, and Martin Holladay hits it head on in this article and others: https://www.greenbuildingadvisor.com/article/makeup-air-for-range-hoods

Fortunately, I came to learn that I didn't need 500 CFM. I'm not sure what the KA unit is actually delivering, but my guess is that part of the reason they spec'd the 500 CFM blower is to pull the air through the constrained passages of this compact microwave. There's no doubt in my mind after opening up this unit that if the blower is true to it's 500 CFM spec, the built in air restrictions plus those on the exhaust side will result in a substantially lower actual CFM (but then one must also similarly question the venting specs of other vent hoods and OTR microwaves). I do know that it vents more aggressively than my old 200 CFM Broan. My main wish is for a low, quiet setting for low-heat cooking and simmering.

we purchased this unit to vent outside but are confused on which vents to cover on top of microwave. directions areconfusing