Purchased a Kitchenaid Range Hood Vent that has a 1200 CFM blower. Instructions say to install a 10" duct vent. My existing venting duct was a rigid but small 6 inch duct.
Unfortunately at demo realized that sewer line and other utilities are right in the middle of the ceiling cavity perpendicular to the exit point, 10 feet away = cannot move (cost prohibitive).
A. Can I used TWO 5" rigid ducts instead of the 10" one required? How? I'd think the biggest challenge will be the multiple reducers needed to go from 10-8, 8-6, for both lines. And a Y-joint somewhere…
B. What if I used the existing 6" duct and merely added a 4 inch line? Or two-6 inch ducts?
(I will also be adding some mineral wool insulation for sound absorption right above the range but the goal is not to have to tear down the ceiling either.)
Best Answer
Here are the numbers and you can see what your options are.
The numbers are as follows:
On the left: CFM (Cubic Feet per Minute, cfm)
On the right: Equivalent Diameter Round Duct Sizes
200 : 4.9
300 : 5.7
400 : 6.6
750 : 8.3
1000 : 9.1
1250 : 9.8
1500 : 10.7
1750 : 11.5