Generally, (or maybe I should write hopefully), fans for hoods have monotonic fan curves so that the fan cannot get into a hunting mode where its speed oscillates. I think two such fans in series would also not hunt, but it is always a possibility given that with two controls each could be run at a different point on its fan's fan curve and that there is a lag between air flow changes at one fan before that flow gets to another. In any case, what I meant above was that the roof fan could be installed and operated with the hood fan turned off. Removal of the hood fan, or its use as a booster, would be something that one determined second. Removal would reduce noise, even if the roof fan were sized to equal the flow possible from running both together. Non-removal but not operated would cause some undesirable flow restriction. I don't see a mechanism for burn-out from series fans so long as they don't hunt. As always, the larger the roof fan, the lower the blade tip turbulence and noise when run at a speed that has the same flow rate as a smaller fan run at maximum. I don't want to try to divine the thought processes of the marketing departments of stylish hood manufacturers. But I imagine that they don't believe their customer base has sufficient interest in that feature. kas

Ours does not have the gap you're talking about but I've seen plenty of them that do and it looks fine. I'll see what I have in my picture files of hoods with gaps. Here's one: This one they added wood filler pieces to make it flush. You could do that too. And check out this website that has lots of photos of different style hoods. Have fun! Wood Hoods

lovestocook... I remember the pics of your kitchen because the cabinets are so unique and beautiful. Contemporary, clean, yet warm and inviting. Your hood suits your purposes perfectly! We went down to the house we're going to renovate and I took a look at the area again. Now I"m thinking of completely changing up the layout yet again so the hood won't be smack dab in the middle of the living area. Rather then try to explain... I"m going to take some pics of the exisitng mess (construction site and all) and post them for ideas. I'm still a work in progress when it comes to drawing layouts so I think some real time pics will help to start the process rolling a little better. If I do change it around, the hood would be infront of a huge 9' long window that has about 18" of space above it before the ceiling and the same amount of space below it before the floor. I guess that would make the window 5' high (DUH!... took me a minute to figure that out!) When I took a tape measure to a spot 30" above a standard height base cabinet I was surprised at how low that actually is. Since the area is going to be all open, I'm not yet sure if I want it in the siteline from family room straight through to the backyard. The backyard is what makes this house so glorious. Thank goodness this is a long term project and we are just beginning to begin. Thanks for taking the time to post pics.

Boxerpups, I am thrilled to hear from you. I so appreciate your taking the time to research pics for me. It is MUCH more noticeable than the Broan pic you shared. I would be very happy if it were to look like any of the samples you posted. I'm also glad for the encouragement that it's possible to have the two pieces smooth and flat -- I swear talking to the contractor and carpenters made me feel like I was going crazy... as if my expectations were outrageously high. They insist that the pieces aren't manufactured properly, whereas the tech support team said they have received zero complaints of this type about this vent, with the caveat that the pieces are very easily bent. I don't know who/what to believe. Ahhh... this too shall pass. And, at some point it will all be done to my satisfaction.