When aiming to capture and contain rising and expanding effluent by choosing a hood size wider and deeper than the cooktop size (or more properly the contour of possible pans used on the hobs), it is the entry aperture of the hood that one wants to have overlap the cooking zone. In the case of the XtremeAirUSA hood image, one may see that the capture width is much less than the overall width, and very likely smaller than the expanded plumes at the hood height. I would guess this is a hood tailored to a price point, rather than optimized for its function.

In spite of providing the hood tourist six images at the link, the Dacor does not reveal anything about its functioning parts other than its exterior aesthetics function parts. However, in its Use and Care Manual .pdf, there is an upward image of a 48-inch hood that suggests that the 36 inch hood may have more of its external size as aperture, and that it has baffles across most of the the entire width. I suggest you get your candidate vendor to provide a photo of the hood you are considering.

kas

Good detective work, Kas. Thanks so much! It does look from your image that the Dacor has decent sized baffle filters. We have not been able to get an image of the underside from anyone (Dacor, store, on-line etc). Do you think the Dacor hood that is 30 inches deep and 36 inches wide is the proper depth for our 30 inch Thermador induction cooktop. What is the recommended depth for an island hood?

Also, is 600 cfm of the 36 inch wide Dacor hood sufficient?

Carol

The dacor wall variant is on my showroom floor. It only has one large baffle in the middle. The island version is identical in that regard

Taken from Dacor's website:

Easy-to-Clean, Dishwasher-Safe Baffle Filters

• 1 (DHI361, DHI421 models)

At the risk of too much arithmetic for this century, the desired aperture should be of such a size that a 10-degree half angle from the pan edges outward is encompassed by the hood aperture. So, if some pans can make the 30-inch cooktop emit over its entire 30 inches of width (not necessarily at the same time), and the hood is "h" inches above the cooktop, then the width of the hood should be 30 + 2h*tan10deg. Similarly for the depth, except it is likely that the pan area is less then the cooktop size due to the typical control area. If the cooking area is actually 18 inches, then the depth should be 18 + 2h* tan10deg. This area, by the way, is the area to center the hood over, not the center of the entire cooktop. (For the Viking cooktop with the controls to the right, just use the potential pan area width in each direction.)

Don't forget that the overall hood size is larger (in some cases much larger) than the aperture one has available to capture the cooking plumes.

Once the desired hood aperture size is determined, and a specific hood selected to meet it (if possible), then the flow rate follows from my usual ramblings, the rationale for which I won't repeat here. Take the area (of the aperture) in square inches, divide by 144 for square feet, and multiply by 135 CFM per square foot to yield the zero static pressure rating of the desired blower. Actual flow may be only 2/3 of this due to pressure losses. (There are various factors that may make more rated CFM desirable, or less rated CFM sufficient; the value obtained by this approach is probably an upper limit needed for induction unless one is gagging the hood with a tight house.)

kas

Edited to correct a bit of brain fade.

Thanks Joe for your comments on the Dacor hood. Glad you describe the baffles in this unit as large.

Thanks Kas for your careful math. Looks like the Dacor is far better than the Xtreme based on size of baffles (capture area alone). I will work through your numbers some more. On a quick look it looks like the Dacor specs will work in our application,. I was disappointed to see in a thread this one that the posters don't like Dacor appliances.

Carol