1) Make sure your carpenter makes the wood surround / hood bigger than the sizes of the insert. so if your insert is 34" x 22" make the hood 36" x 24" ish if possible or even bigger. 2) Recess the insert 6" up into the cabinetry to create a larger capture area. Think of this as an upside down sink, the insert is the plug hole and the bowl is the wooden frame. The bigger the frame the more smoke and grease will end up going out of the house. 3) Insulate the gap between the wood and the insert. 4) If possible make 2 x 45 degree turns above the hood instead of 1 x 90 degree turn, this will reduce noise and friction.

Thanks for help. FWIW, the distance from concrete soffit to floor is 7 feet as expected. I have narrowed it down to either Zephyr or Kobe insert liner as both have the horizontal vent in the rear. The horizontal attachment will be moved slightly to the left as that will be where the new cooktop will be moved. I am assuming that there will be some kind of attachment to the current opening which vents to the building's venting system - whence it goes after it leaves my kitchen I have no cares as long as it passes inspection. I am not familiar with either of these brands - does anyone have any recommendations as to one or the other. My venting needs frankly are minimal as I don't deep fry and will have an induction cooktop. I am considering mid range in each brand: KOBE CORE COLLECTION - This retails for about $850. It's ADA compliant with a remote which seems like it would be more convenient than reaching for controls under the cabinet. Monsoon I Insert Monsoon I takes one-piece liners to the next level. Includes dual-level halogen lights, and ADA-compliant wireless remote control, 6-speed electronic controls and either a powerful 600 CFM blower (30″ and 36″ models) or 1,200 CFM blower (42″ and 48″ models). ACT™ available on all models. Vertical and horizontal Zephyr - I couldn't find any functional difference in these two models except one has slightly higher CFM but I am sure the lower would be perfectly adequate for my needs DELUXE IN26 SQB-650-5A BUILT IN / INSERT 30" - 36" 700 CFM $803.49 PREMIUM IN2630SQB-700-2 BUILT IN / INSERT 30" - 30" 750 CFM Build.com $771

I think it really depends. Nothing that moves that much air is going to be quiet. If you can have remote blowers and inline mufflers, then you can reduce some of the sound; and in that case, a VAH might very well the obviously inferior choice. But even then, you still have the noise at the baffles. So, don't expect the hood to be whisper quiet. We have a 20 odd year old VAH. As long as the vent pipe is adequately sized, it works great and noise level is IMHO in the expected range. We also have a new ModernAire hood with internal blowers. It has more power than our old VAH, but it can be really really loud. And part of that is simply the whistling sound that the air makes when it passes the baffles at full air velocity. If I turn down fan speed, it's about as loud as the old VAH. In other words, I don't really perceive a big difference between either designs. Pick what works best considering all your other design constraints. And absolutely make sure that your vent pipe is as large as you can make it.

Where duct equivalence is a requirement, two 8-inch ducts could be used to match a 10-inch duct. In any case, searching this forum should have led to commentaries on determining requirements before picking hoods. Decide how much cooking plume effluent you want to capture by how much the hood overlaps the possible cooking pans and locations. (Assume a 10-degree from vertical plume spread.) Then use the area of the resulting hood to determine needed air flow rate when performing hot cooking (even if it is on only one burner) by multiplying the area in square feet by 90 CFM/sq.ft. Then, for the case of going directly out the wall with free air flow MUA, assume a factor of 1.3 for baffle pressure loss. This will raise the rated CFM needed for the blower by 1.3 such that the rating should be 1.3 x 90 x area in sq. ft. (Note that this is less than the 1.5 I usually suggest for normal duct lengths, less than perfect MUA, and a duct silencer.) If the hood or insert is a VaH without baffles, use 1.1 to compensate for minor losses such as from the outside cap loss and imperfect MUA. Example: 45 ft x 2 ft = 9 sq. ft. Desired flow is 9 x 90 = 810 CFM. Rated flow for conventional baffled hood then should be 720 x 1.3 ~ a nominal 1000 CFM. While equal blowers mounted in the hood or just outside via a minimal duct length will have roughly the same noise, outside mounting may allow a larger blower that one can run at less than full speed. This will greatly reduce blade tip turbulence noise, which otherwise dominates. Abbaka and Wolf and Broan, for three examples, make down-roof radial blowers that should be adequate to mount on a wall. Exterior aesthetic considerations may influence inside vs. outside, but a low pressure loss cap will not be much larger than a motor housing, and you get a damper with the housing.