Hopefully, no one will bonk their heads.

You are talking approx 68" off the floor. Someone will split their head open on it. Upper cabs are 53-54" off the floor and very visible. At 68" it is not visible because people don't look up. I bloodied my nose twice and broke my glasses on floor joists in a deep crawlspace, they were at 64", and I'm 5' 9". Never saw them. We fastened vertical boards to all the joists in the construction walk area after my mishaps.

hendricus: So, you are saying it should be lower so we can see it, even though lower makes it easier to bang into? Seems counter intuitive, but I get your point. At the moment, when we test it, our heads are under when we bend forward and it is not in our way visually when we look across the room. We'll try it out a bit lower. Thanks.

In my view it is high enough when it doesn't hit your head when you approach it or bend over the cooktop. You may want to extend that rule to apply to persons of somewhat greater height who might also use it. Lowering the hood, while perhaps increasing its effectiveness, will interfere with bending over and possibly interfere with sight lines to the cooking utensils. (Glass canopy shapes I've seen have poor capture, thus raising one higher may not be much of a penalty.)

A related issue is how far built-in lights (if any) are from one's hair (if any).

Front to back mounting should try to align the air intake center with the center of the cooking area, and not necessarily the center of the overall cooktop or the center of the island.

kas

Thanks Kas, always good advise.
Carol