First off, great choice on the 27" depth. As far as raising your hood to 36", I would say absolutely not. I've got mine set at 30" over a 30" Bluestar and it's as high as I would dare put it if i want it to do its job. I'm 6'1" and have never bumped my head. Admittedly, it requires a certain level of awareness (particularly when dealing with the back burners) but I'd rather adjust my body than smoke out my kitchen.

The best answer to this question was posted a while back by kaseki, who I regard as the ultimate authority on hood ventilation here on GW. The link is below, and you should read his post carefully.

The short kaseki answer though is to estimate that effluent moves laterally 1.5 inches for every foot of rise. Thus, adding 6'' of height to the hood requires that you add at least 0.75'' of coverage on both sides and front as well. That's doable, it sounds, but maybe if kaseki is reading he can chime in.

Here is a link that might be useful: choosing vent hood depth

Thanks to all for the info. Keitel, I'm guessing that the reality of the situation is that your arms are long enough to allow you to cook (at least on the front burners) without having to duck seven inches (if my arithmetic is correct)? And therefore you're actually standing back a bit from the front of the hood (thus preserving your forehead)?

Our hood is mounted 29-3/4" above our cooktop surface. I'm 5'10" and my DH is 6'5"...neither one of us has ever hit our heads on the hood. You don't lean over the cooktop to cook (you'd get steam/grease in your face!), you reach in. The few times you do lean in to check something, you're moving down as well as in so I think you automatically adjust. However, I worried about that when we were shopping for a hood and got a hood with an "emerald lip" that does not have sharp corners on the sides or along the front. It turns out it hasn't been an issue, but it does look nice!

(Vent-A-Hood, SEPH18-242)

I am 6'2" and chose to get a 24 inch deep model rather than the 27" after "testing" both with cardboard box mockups. The 27" just seemed uncomfortably close to my face while cooking. I suggest you try this yourself and see how it feels to you. Personally, I am willing to let a bit of smoke escape from time to time rather than have those extra three inches of hood sticking out into my face.

Whatever you do, I definitely second the recommendation to choose a model with a rounded or beveled edge (I have the Emerald edge model).

You called?

Sorry for the late response, I am now busy with my kitchen reno.

It is important to temper theories with their own modeling limitations. The measured and modeled effluent expansion angles, which vary with stovetop conditions, apply to very still air in laboratory settings where large, low-velocity diffusers are used to supply make-up air. In home environments where people are moving about, opening doors, etc., the effluent expansion can increase or bend in some direction. This is more of a problem with a peninsula or island configuration than a wall configuration. If the hood is marginal, some smoke, grease, etc. can escape immediate collection. How annoying this is has to be weighed against how annoying hitting one's head is.

Even though I am rather intolerant of some cooking smells, I opted for a nominal 36 inch height (actually 34 inches due to ceiling height). This puts the hood just over my head. I selected a hood that overlapped the cooktops all around, and used a large exhaust fan. I also have another ventilation fan system to remove odors from the oven area. I expect (or at least hope), but haven't proved yet, that whatever effluent initially escapes capture will be modest and not last long before being picked up.

As I have recommend before, sketch out a side view of the stovetop and hood layout, put in a stick figure, and determine whether there is much risk of injury, or whether visibility of the contents of pans on back burners is obstructed.

The bottom line is: higher requires larger for the same capture success. Larger requires more cfm for the same containment success.

kas