My first thought - you are crazy to use a ductless. But I read your post and my answer is going to be really easy - don't put a vent hood in. There is a custom house that was for sale next to us when the people couldn't close. I think as a cost saving matter, they had no vent. They had what I'm guess is a mantle type cabinet (I'm not exactly sure what that is but I think I know). You looked up from the range and it was a flat piece of painted drywall. I'm sure they installed a light or two. That gives you power in case you ever want a vent. As an aside, it turns out they roughed the duct in, so I'm thinking that they wanted a nice hood so where going to wait until after closing. This is all in a strict inspection/code town. Forgive me if I get the terms confused but in my mind there is a liner a blower and a hood. I think you already have a planned cabinet hood (mantle type) so you aren't really asking about a hood. It is the liner and blower. I would be surprised if anyone made what you are looking for. There are recirc vent hoods but they wouldn't be invisible or covered by a cabinet. You could probably take the guts of a ventless hood and make what you want very easily.

Since your range placement is set, you have three options: move plumbing pipes ($$), hide with soffit as you mention, or change to under cabinet vent hood. Of the three, I like the under cabinet vent hood the best as you can then order the trim from Ikea to align with the other to the ceiling trim. That's provided your HVAC team can deal with either the pipes (10 x 3 inch ducts) or go lateral a bit. I know it's frustrating to be in your position. For a small kitchen, having cabinets over the range (30" above burner surface) offers space for cooking and baking items and helps to keep you from moving all around the kitchen. I found that handy in fact. Your kitchen designs look nice btw. Enjoy.

Ah. My apologies for abusive engineering descriptions. Sometimes I tend to unconsciously assume that all the previous stuff here has been read and digested, so all I have to do is present a reminder. Capture: The plume expands as it rises. The actual expansion angle is greater than 10 degrees outward, but ten degrees encompasses most of the higher velocity components for relevant cases. This means that the cone is wider the higher one measures above the pan base. At 36 inches hood height, for example, with a tangent of 10 degrees equal to 0.176, the plume has expanded outward by 36 inches times 0.176 or 6.4 inches. Similarly, for 30 inches, the plume has expanded by 30 times 0.176 = 5.3 inches. (Exactness is used here to clarify the calculation, not assert a defined boundary exists at the plume.) Suppose a pan base's maximum extent from the wall was 19 inches (which would be true of my induction cooktop if it were against a wall). Then one should aim for a hood aperture that was 19 + 6.375 = ~ 25 inches from the wall if 36 inches up. A 27-inch hood with lights in front of the aperture is close enough. Hence, your drawings have the angle going the wrong way. Imagine a really large traffic cone (without it weighted base). Slice it where it is the same diameter as the pan base and invert it over the pan. This inverted, truncated traffic cone, or rather a set of them perched on all the burners or hobs, can be imagined as defining the required boundary of the hood aperture. The desired hood aperture for good capture is independent of whether the structure of the hood is all metal or is metal inside of wood. Depending on your configuration, it may be best to space a smaller hood outwards and fill the gap at the wall side with some sheet metal. Side cabinets can help perform the function of side curtains in commercial configurations. (Note re pillog's comment. There is a small zone of high flow rate at the edges of the hood, and this has the effect of a slight increase in effective aperture.) Containment: Your analysis is correct. If the aperture is 6 sq. ft., then the desirable actual flow rate at full power is 90 x 6 = 540 cubic ft./min. Now where did I pull the magic number 90 from. Briefly, there are studies that have been published of plume velocities as a function of surface temperature, with induction and with gas. The gas cooking velocity (because the gas combustion products are entrained in the plume) causes more than a meter per second of plume rising velocity. The velocity with induction is typically less than a m/s. At the pan, the hood has NO effect on the velocity, and this essentially holds until the plume is close to the hood aperture. Another way to put it is that the hood captures the plume due to the plume's upward momentum (mass times velocity), which will not change until accelerated or decelerated by some force. When the plume reaches the baffles, it can intercept a gap and pass into the baffle space, or it can hit a metal part and potentially reflect. To keep the reflection in check, the air flow velocity of the hood has to be enough to change the reflection momentum to near zero and let the plume part be pulled into the baffles. When the air velocity is 90 ft/min average across the baffle space, it is about twice that at the baffle gaps, and this velocity is equal to that of the plume velocity. Also, I have observed this level working for the plume over my induction wok, and Greenheck suggests 85 ft/min for similar cooking (Figure 4, page 9 of the previous reference). So think of 90 ft/min as a suggestion that I don't think will prove to be too low. Too low of a hood velocity (CFM/sq. ft.), hence too low of a hood flow rate (below). Enough velocity (below) Blower specification: Yes, the factor of 1.5 is used to make up for the fact that blowers are specified by themselves (usually) hanging in free air, and what you have is a restrictive system that has to deal with baffle restriction, duct, and make-up air pressure losses. The relationship is given by the so-called "fan curve." For example, the Broan blower fan curve immediately below is just about done at well under an inch of water column pressure. Your requirements, depending particularly on baffles and MUA, may require a more "powerful" (higher nominal CFM) blower, as in the second figure. If the only loss were baffles, then the first figure would be barely good enough, because the baffles might have a pressure loss of about one or two tenths of an inch, w.c., at 90 CFM/sq. ft., depending on their aerodynamics. Throw in ducting and pressure losses in the MUA system (a whole giant topic of its own), and the tenths of inches build up leading variously to a need for one of the higher nominal flow rate models.Ekes out 540 CFM at a very low pressure drop (above) A blower with the 1.5 factor achieved (above). Keep in mind 1.5 is only a guess. A blower that would make up for many installation crimes (above), but which drives an unnecessarily more expensive MUA system to keep house pressure up. kas

When I was 20, my roommate and I went on a vacation to the Cayman Islands. One day, a trio of 3 men beside us on the hotel's patio (they looked to be mid 40's) started chatting with us. The said they were childhood friends, and always went on a vacation together every few years, to go deep sea fishing. They said their wives went together the same week, to some other vacation destination. They had rented a boat for the next day, and hoped to catch some 'big fish.' They said if we felt like getting offshore for half the day, we could meet them on the beach the next morning and join them. They explained that it could get pretty boring waiting for a bite, and being childhood friends who'd shared every story possible, they'd welcome some different conversation...but one laughed and added that we should feel free to bring something to read, in case we found them too boring. We asked how their wives would feel about their invitation. All 3 said their wives wouldn't be upset, as they knew their husbands frequently invited a few people to join them, and that they implicitly trusted their wives as well. So we agreed to meet them on the beach the next morning, with our packed lunches and nothing else. Just before we boarded the boat, one of them mentioned that the ride out to where they needed to go, could be pretty choppy. He offered us some Gravol, to avoid getting seasick, which we took. The pills looked 'normal' and it was back in '76, so we'd never heard of date rape drugs back then. Indeed the ocean was pretty choppy on the long ride out to sea. About an hour after they stopped, I started feeling really sleepy. My roommate later told me she'd been captivated, watching one of the men struggle to reel in a large fish for about 20 minutes. When he finally landed it, she noticed I was nowhere to be seen. She was told that I'd almost nodded off in my seat, so had gone below deck to lie down for a while. My roommate said she went down, but I was asleep, so she went back up top. Less than an hour later I awakened and rejoined everyone. Nothing was amiss, and I felt refreshed after my nap. Not long after, I watched a shark being caught and released, as it was deemed to be too young. When we returned to shore, the men were thrilled that one of them had landed a big fish that would be mounted and brought home. The next afternoon, we saw the men come back in, with 2 guys and a girl they'd apparently invited along, but no big fish. So my roommate and I were thrilled we'd been part of a successful deep sea fishing excursion! But as a mature adult in today's world, I realize how bad things could have gone. In our naivety, we'd gone with 3 virtually strange men, out to sea. No one at the hotel would have known what happened if we'd disappeared, and certainly not our families back home. There weren't even any witnesses on the beach at 5 am, or on the hotel patio when we'd left with them. Although the Gravol just made me sleepy, it could easily have been a totally different pill. Even if the men really were 'happily married to implicitly trusting wives' we still could have been killed and just dumped overboard, way out at sea. No one knew we were on board and sharks would have eaten the evidence. So my roommate and I were very, very fortunate that these truly were a trio of honorable men, who were at all times courteous and respectful to us. That still stands as the most foolish and potentially dangerous thing I ever did.