The first question I had was whether these 16 inches of filters are "approached" by internal sides that direct the cooking effluent to the filters. Commercial hoods to not have filters across their entire front-to-back depth, but direct the uprising air to a narrower band of filters. On the other hand, if there are only 16 inches of effective aperture in a 25-inch deep hood, then shame on Abbaka.

Ideally, your hood aperture should extend beyond the cooking surfaces (pans on hobs and burners. The amount of extent depends on the distance from pan base to hood aperture. You might choose how different hobs are used so that the hood is more centered over the cooktop hobs and gas burner that will be assigned to the most greasy cooking, and leave tea water heating to the edge hobs.

The front-to-back hood center should be over the center of the pans to be used. This may require that you space the hood out from the wall and insert a SS panel at the back to direct the rising thermal plume effluent toward the hood aperture.

kas

Thanks for the tip regarding how the filters are placed in commercial hoods. After your comment I looked at a couple diagrams of commercial hoods online. I think I have a clearer picture of what your described. I'll be calling Abbaka Monday morning!

And regarding the width of the liner......is it also possible to use my custom enclosure to help direct the effluent to the filters, depending upon how it's built? Some of the commercial diagrams were cross sections that revealed angled banks of SS at the perimeters.

Thanks
riveroakgirl

Yes. You can angle SS from the edges of the custom enclosure. In my view, this SS sheet should have a bend at the bottom to cover the bottom edge of the enclosure to protect the wood.

Note that the point where the slopes begin at the bottom of the enclosure defines the true aperture, and the air flow velocity there has to be some minimum to assure containment. So if you increase the aperture AREA by 2, then the flow rate (CFM) should double over what the original aperture could get away with for whatever area it could actually capture over. (I think the reason is a fluid dynamic parallel to the Lagrange Invariant for light -- you can't concentrate the smoke without reducing the upward component of the momentum vector, so the air flow is needed to add an upward component to the vector. A large hood aperture that went straight up to the outside via a monster duct without any reduction in size probably wouldn't need much of a fan.)

kas

kaseki
I spoke with Abbaka today. Apparently the liner does not have internal sides that help direct effluent to the filters. In fact, I was told that the liner is quite flat - without any degree of angle at all. I was surprised at this. And the price turns out to be not that great with these clarifications in mind.

I have since talked with Prestige, Tradewinds, and attempted to contact Modernaire. Regarding Prestige and Tradewinds products - they are both rather shallow at 6-7" high. And the angle at which the filters are placed is also quite small - both around 5 degrees. Do you have any thoughts regarding the impact these features would have on capture of effluent? I looked at the Viking hood liner and it is pretty tall at 18". Just not sure about the quietness of the Viking. I don't think I had mentioned previously that the kitchen is part of a great room configuration, so quietness and efficiency are key priorities. Thanks again for any help.
riveroakgirl

Flatness itself is not the issue, inadequate aperture is the issue. One could have a 24-inch deep aperture with 16-inch baffles so long as there were some rising sloped sheet metal to connect the two.

Baffles should capture grease with about the same efficacy no matter the angle. Commercial hood baffles have to be at a steep angle above 45 degrees (IIRC) to drain grease. In residential use, routine washing should be adequate. I think my Wolf hood baffles are at only around 20 degrees. However the two banks of them cover nearly the entirety of the aperture area which is large enough for capture. (Front-to-back actual aperture on my Wolf Pro Island hood is 24.5 inches.)

I assume then that you have a hood that is externally 25 inches front-to-back, but only 16 inches is actually aperture. This would likely be inadequate to capture all the cooking effluent from front burners. One really needs most of the 25 inches, depending on configuration and trapping effects of walls and cabinet sides and height of the hood.

Quietness generally requires an external fan and an intermediate silencer/muffler in the duct. At best this will leave only aerodynamic turbulence noise around the baffles, which should be tolerable at normally adequate flow rates.

kas

Hi, Riveroakgirl. I realize this is a very old post, but I am considering getting the Thermador Freedom Induction cooktop along with the Wolf multifunction/wok gas module. Did you end up getting these two cooktops? Are you happy with them (and the combination)? I'd ask which hood you ended up going with, except my cooktop will be placed in an island type set-up.

Just for reference, my 36-inch induction cooktop and my Cooktek induction wok are mounted on a peninsula and encompassed by Wolf's largest Pro Island hood. Care must be taken for adequate support for the cooktops while using rational cabinet designs. This tends to lead to more unit separation than one might initially expect and hence wider hood sizes for coverage.

Thanks for the input, Kaseki. Ours will be on a peninsula, too - and I'm definitely trying to get my head around the hood aspect of this choice. The necessity for a hood is a disappointment since the peninsula divides our kitchen space from the family room. (I was originally planning to go with a ceiling vent but, upon a second visit to the store where I saw the ceiling vent, a different salesperson told me that the vent was pretty ineffective if built into the ceiling as a soffit/platform.) Part of me thinks I should just compromise on the cooktop portion of choice so that I don't need such an expansive hood - and part of me just wants to get the cooktop I will most enjoy cooking on! (There is also a possibility to insert a range instead of a cooktop, but I'm not sure I want to give up any aisle space between peninsula and island - and plus I think range would complicate and/or nix my wish to combine induction & gas. The only advantage to putting in range would be that some of the cooktops seem more powerful & better configured when set into range - and of course the benefit of a second and wider oven...)