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

I agree with rpg51. Down drafts can and do work when they are vented correctly. I worked for Jenn-Air (pre-Maytag / Whirlpool) and saw many in-home installations. Most done properly and some not so good. ie. back to back elbows, wrong size duct work and flexible duct work. Are they perfect? No. If you know what the limitations of a center down-draft are ahead of time you'll not be disappointed. Rear telescopic down-draft work very well too. Again, with all venting it needs to be done properly. Best Cattura 18" Down-Draft With regards to the Best Range Hood Cirrus built-in hood. Yes they do work. See the video link below. Here is my question to you. Who in your house is climbing-up the ladder to take down the filters and clean the stainless. Maybe not be bad at 9-ft leve but may be more of a PIA in at 12-ft. height. Best - Cirrus Range Hood Please note that the comments made by Futuro Futuro Kitchen Range Hoods is a company that does not offer a down-draft or true flush mount ceiling hood. If seems that if they can't complete in the category it is much easier for them to poo poo the options you are considering because they don't have anything to offer. To be fair to Futuro their hoods look like a direct hood import from Italy and seem to of reasonable quality. But, unless you're in Brooklyn, NY or Hallandale, FL it is difficult to truly judge the quality and the long term support for service. Ask those folks that who own a Elitair or TecnoWind hood and that are now orphaned. My recomendation is to look towards a nationally distributed brand and your local dealer for suggestions and long term support. Please let us know what you finally decide. Good luck.

Odor elimination requires complete capture and containment of cooking plumes. These plumes expand as they rise, deviate due to drafts from hot air furnaces and/or air conditioning, and spread due to turbulence from moving people in the area. Normal hoods are placed in the zone between 30 and 36 inches above the cooktop. That is, to 6 feet above the floor. Commercial hoods, usually larger in capture entry area, are typically set at 7 feet unless one counts ceiling systems. (See Heydal's ceiling for example: https://cms.esi.info/Media/documents/Brita_heydal_ML.pdf) One can always use a commercial system that grows appropriately at any height. However, these are not only large in plan view, but tall in elevation view. On top of this, you need to consider, or specify, what your ceiling and joist characteristics are and if there is an attic above or a living space. Wolf makes a ceiling mounted hood, and the descriptive information appears on pages 139 through 142 of the Wolf Design Guide, available at Wolf's web site. The available units are only 21 inches wide in the short dimension. I would consider this to be ineffective in capture of any significant plume such as hot oil cooking (searing and wok cooking). I'd want a 5 ft x 4 ft aperture at 8 feet up, and thus embedding a custom commercial hood into the ceiling would be necessary if buying three of the wolf 4-foot units wasn't practical. Also, please note, I've never seen one of these, and have no idea whether I would consider the design details acceptable. I would think that such a collection area would need 1500 CFM rated (1000 actual) if we assume significant degradation of plume upward velocity; even more would be required otherwise. Make-up air is required for this level of flow rate. Most locations will need heated MUA. With filtering, the MUA might be OK passive (without blower), but if there are any combustion appliances that are using air from a space connected to the kitchen then a blower-driven MUA will be needed. (MUA threads here may be viewed for background.) If you want to consider a commercial based hood as a likely better choice if there is an attic above the ceiling to fit it into, @opaone may come by and provide some additional information, including what I don't know for gas flame combustion products expanding potentially wider than the cooking plume and air quality effects resulting therefrom.

How about grease on the ceiling? In the first image below from Victory's website, the size of the single device is smaller than the plume size at the ceiling. Even though the slots can pull from across the ceiling, impinging plume effluent will deposit moisture and grease. In the second image, the larger area and lower height will be more effective, but a more conventional hood will be better for the same area, else commercial kitchens would use a different design. Also, note that the higher the aperture, the more the plume can be deviated by relatively mild drafts, and the greater the plume disruption due to people moving about. Obviously, the trades among affordability, performance, and aesthetics are up to the home owner, and to each his own. As one who weights performance within the limitations of the architecture most highly, my choice would be different.