If you want to go up the interior wall, I suggest that you build the wall with 2 x 6s to provide 5.5 inches of internal gap. Then a 4 or 5 inch by 12 or 14 inch duct will fit. This will cost two inches of room on one side or the other. Eight inch circular duct has an area of about 50 square inches. 4 x 14 is a bit more (56), but square duct has more frictional pressure loss than round duct. If I were doing it, I would use fire-code sheet rock on those walls, and insulate the duct with mineral wool. This would minimize possible rattles from the blower, which I would put on the roof if possible, and provide some slight additional protection in case of a grease fire. Use only galvanized steel duct (stainless steel would also be OK :). kas

Wow, thank you soo much for all of your expert advice! To clarify a little more. I only cook for my family of7 during the week (besides for a once a week lunch on campus for 25 or so:) But the thing is I've been doing this for 10 years with only one little residential range so I don't think i need a serious upgrade to a commercial. Maybe. But I don't know if I want to go the whole fire hazard, high cost ventilation, no wood cabinets nearby etc route. I've got 5 little ones running around me all the time! As far as the religious configurations, yes Chef Dupre you've got me, we run a Jewish Home Away from home on campus here in UVa--but the pilot light would not be a problem on sabbath. But the more high tech ovens do have a Sabbath mode that would be helpful as well as a self-clean which is very useful around Passover. The bottom line is I'm not ready to put a commercial stove in the middle of my new homey kitchen. So you'd recommend putting two 30nchers next to each other before the 48inch? Or a double wall oven and professional cooktop. I do have to admit I love the look of those professional ranges... Thanks for letting me talk things out here and any more advice about brands and experiences would be more than welcome!

The DCS AG range RGT-305-N has I believe a total of 77500 btu's for its burners. The rough rule of thumb is to have 10 cfm's per 1000 btu's of burner capacity. That means you should have a hood that has approx. 775 cfm's. Naturally, you can assume you will not have all 5 burners going full force at once, but on the occasion when you are grilling steak on max heat, or frying fish, you will be happy to have the higher cfm's. On other occasions, you can just use the lower setting on the hood. In any case, I would not go lower than 600 cfm's, and that's assuming you never fry. I didn't see the convection OTR MW you mentioned on the DCS website, only a non-convection OTR MW. In any case, the DCS OTR MW doesn't even list how many cfm's it has, but almost all OTR MW's are 300 cfm's or less. So, you can see how inadequate its fan will be. Furthermore, there is the issue of capture area. An OTR MW just has a couple of small squares toward the back for exhaust. They are completely inadequate to capture the smoke and grease from the back burners, much less the smoke and grease from the front burners which they don't even cover. Also, because they are small, the mesh will become clogged with grease very quickly, and become even less effective. People who have the space actually will install a hood 6" wider than the range, to add 3" of capture area on each side; this is ideal, though many do not have that space, so 30" wide is fine too. I just wanted to illustrate how inadequate is the capture area of an OTR MW. Also keep in mind that an OTR MW works poorly in an active kitchen from a "flow" point of view. These machines are really for the small kitchen where there is truly no other place for a MW other than OTR. You didn't mention that space constraints were an issue. When the MW is OTR, it means anyone using the range will have to stand aside for someone who wants to use the MW. The height of the MW makes it difficult to see inside it if you or family members are at all height-challenged. Also, it is not easy to pull hot, sloshing dishes from that height. Also, the MW is mounted much closer to the range than a hood would be, making the range cooking area feel "hemmed in". If you do decide to install a proper hood instead, make sure your exhaust ductwork is large enough. Most hoods require 8" diameter duct, though you can find a few that allow 6" diameter, but they are harder to find. My final note is that if you are determined to buy an OTR MW instead of a proper hood, keep in mind that the DCS OTR MW is a re-badged Sharp. You can buy the Sharp for about half what the DCS will cost. The amount of profit in the rebadged MW's (Wolf, Viking, etc. all use rebadged Sharps or Panasonics) gives salespeople a lot of incentive to push them. Having said that, if the look of the MW door and the DCS badge are important to you, then it will be worth it to pay the upcharge for the DCS version.

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.