This would be like having a cooktop on an island but with a little more protection.

Unless you cook in a literal laboratory fume hood, cooking fumes are going to be escaping.

What is going to be on the ither side of the hole? You will have splatter from the cooktop too.

So the same as an island with a hood??? That's done plenty.

It would be the same as an island hood, but instead of small spatters landing in the kitchen somewhere, they'd be staining whatever was on the other side.

As far as fumes and stuff, you'd not be able to rely on "normal" hood sizing. The hood would need to be larger, it's capacity greater and you might need to start thinking about make-up air. It's got more engineering than I do, but that's where you provide a nearby leak of outside air so the hood doesn't exhaust all of your heat or A/C.

Can you architect tell you how many folks have taken his advice. You can then contact them. Good Luck!

I have to disagree about "spatters" staining whatever is on the other side. It would be no different than the front surface, floor in front of the cooktop. We had a cooktop on an island in the house I grew up in, and the back of the island was white and it was neither dirty nor sticky. Very rarely my mom would cook something and then feel like she had to wipe the floor behind the island just in case it was greasy. But it's going to be the same in Front of the cooktop too, and I rarely see the fronts of cabinets under a cooktop markedly covered with spatters. Unless the entire kitchen is a mess because they are careless with everything . Of course if you cook at high heat and toss things up and out of the pan like they do in a restaurant, you may get stuff all over.

I have a pass through opening behind my stove and under the hood vent. It is there because I love the view of the trees across the street which I can see while cooking. The room on the other side of the pass through does not get noticeably greasy at all. The down side is that I find it hard to decorate that wall on the other side as the pass opening just is an framed hole in a large wall that doesnt really go with anything. But greasy? No

Your appliance person is exactly right. Some architects come up with “cool” ideas that are completely contrary to real life. Think about what you’ve wiped off the stove backsplash before, and how many times you’ve thought “I wish this were see-through.” Good luck!

It does not have to extend all the way down to the counter or cooktop. The opening could start 8-12" above the cooktop to create a partial backsplash.

It would be far better to have ”windows” to either side of the cooktop than behind it.

http://finishedkitchens.blogspot.com/2012/11/shanghaimoms-kitchen.html?m=1

https://www.houzz.com/discussions/2663096/finished-vintage-cream-in-the-city

The purposes of make-up air are mainly these: (a) No air leaves the kitchen via the cooktop hood that isn't replaced; and (b) If air isn't replaced with low pressure loss, the household pressure drops to the point where the hood blower can just keep up with the leakage that exists at that pressure. In this case one risks back-drafting any household combustion appliances that might take air from the household common air space.

This is a safety hazard and is the reason why most code enforcement authorities will require MUA if the hood blower is rated for more than 400 CFM. Unfortunately, even if the rating is 400 CFM or lower, one is of depending on household leakage, which is an undesirable method of supplying MUA. Also, for many of the cooktops of interest in this forum, a rated 400 CFM hood system provides too little air flow for complete cooking plume capture and containment.

To the OP's question, without a wall behind the cooktop, there is an additional side of the cooking space where hood overlap must extend past the cooktop, just as for island and peninsula applications. One might want to review the Wolf Design Guide for examples of island hoods vs. wall hoods. The back and side overlap may force the cooktop farther from the wall line, or make the "view" space wide enough to accommodate the hood width.

(If this view space is a cut-out like shape, then possibly a wide and deep enough wall hood could be mounted on it above the "view," but the hood depth will need to be in the 27-inch regime, and the cooktop appropriately placed so that the center of the cooking zones can be centered in the front-to-back dimension of the hood entry aperture.)

I have no personal objection to this design, but the increased costs of a larger hood, larger ducting, a larger blower, and a larger sized MUA system need to be considered. The OP may wish to tour the large number of hood and MUA threads on this forum for improved perspective. Most locations will need, if not require, heated MUA.

@palimpsest, I'm judging by the vast amount of crap ON my backsplash. My hood is 36" above the counter and I have managed to spatter it with sauce. If I didn't have the hood and the backsplash to stop that mess, I'm sure it would travel to the Eastern Shore.