Curmudgeons-R-Us Please review the first dozen or so pages of the guide at the link below for insight into the methods used to meet the goal of proper kitchen ventilation. While theoretical for me (I don't have a commercial hood, only Wolf's largest Pro Island hood) it is not theoretical for Greenheck (or their now spun off ventilatiion division), or for the ventilation system of our forum's @opaone. https://www.tagengineering.ca/wp-content/uploads/2015/02/KVSApplDesign_catalog.pdf I think I should also supplement this thread with the thought that some recent ceiling vent schemes (not technically hoods) use slotted edges for their apparent air intake. While their noise behavior may exceed that of a large area of baffles, they may also provide an effective expansion of the capture area by pulling air across the ceiling -- if designed to do so. Now we have a larger effective capture aperture, as desired, but (!) if the ceiling is not warmer than the cooking effluent at that height there will still be condensation onto the ceiling. It boils down to what you expect to be cooking. I would argue that wok cooking and steak searing will not be captured well, that bacon simmering may be only partially captured due to its low upward plume velocity causing spreading into the room air, but steam and steam embedded grease particles that don't attach to the surrounding ceiling will be captured. And don't forget that the plume expansion angles that one can find in the Finnish cooking report do not account for air turbulence from people moving about in the room, or drafts due to heating or air conditioning. It is always best to capture as low as possible as limited by sight lines and head clearance. In commercial settings where capture and containment is provided by ceiling systems, they cover the entire ceiling and use special techniques to disassociate grease in the plenums above the ceiling. Heydal photo

What did you end up installing? I am thinking of doing the same/ have the same issues and would like feedback.

You *could* mount a "power pack" or "insert" type of range hood, made to fit in a custom hood, at the ceiling level. However, at this height you would need Two of them to have a good capture area, and even then there would be compromises because they are made to have the best function at 5'6" to 6' and the Sorpresa are designed to function at 7-9. So there is not real savings because you would be paying for two units and two sets of ducts etc. These hoods are also sort of controversial and some insist that they can't possibly be effective. (My feeling is better than nothing, but this is a pricey better than nothing). My other concern is that if they *do work, they are attracting a lot of grease and steam to the surrounding ceiling. I would probably want to design some kind of "capture" area in stainless or painted metal to surround the hood so it could be cleaned even if this was flush with the ceiling (an additional pricey detail, I'd think)

A wall location is much easier to accommodate cooktop ventilation than an island or peninsula configuration, but the extent of this truth somewhat depends on what is above the ceiling, and what the ceiling height is, and whether this is new construction or a renovation of existing architecture. The higher the hood entry aperture, the larger it has to be. Conceivably, with an 8-foot ceiling, a one-foot high assembly based at 7-feet height might be feasible. It would have to be commercial sized in its entry aperture (say 6-inches of cooktop overlap in all directions -- 3 x 4 over a 2 x 3 cooktop). In such a case, it could still have proper (albeit low angle) baffles and a containment volume above to a duct to outside. Cleaning would be more difficult with a hood base 48-inches above the cooktop than with a hood base 36 inches above the cooktop. I am not aware of any such hoods provided by the higher-end residential hood manufacturers, but am confident that if suitably encouraged, a tailor-made (bespoke) hood by ModernAire, for example, could be fabricated. You would still need a path to the outside, either through an attic, or chase in a room above, or horizontally if the joist heights provide sufficient sectional area. Twelve-inch duct might be needed. With sufficient floor stiffening, a deeper hood could be inserted into the joist space (in new construction) by framing out the area and providing a horizontal feed to an appropriate joist path. With additional height, baffles higher in the assembly could be used and potentially modestly less CFM would be needed. However, vertical ducting is greatly preferred, and avoids the potential for grease accumulation. Please be aware that the higher the hood entry aperture, the more susceptible the rising and expanding plumes are to transverse drafts, and even turbulence from people moving about. If there is a static direction of flow from air conditioning, for example, some growth over my 6-inch comment may be needed.