Why is combining it with a microwave inherently bad? As long as there is an air channel to the exterior, the critical thing should be air volume over time, no? (CFM or m^3/minute or whatever)
I am assuming that effectively all microwaves move less air than dedicated range hood. From cursory Googling, microwaves vent at 300cfm to 400cfm, while dedicated range hoods can move 600cfm to 2,000cfm.
