Range hood vent through roof or gable end?
pbyar
| Posted in Energy Efficiency and Durability on
Claimed 760 max cfm range hood. I suspect 300 cfm actual will be closer to the truth. Make-up air issues aside, 6″ round, mastic sealed metal duct can go:
-up 7 feet (5 feet from ventilated attic floor) and out through 4:12 roof facing prevailing winds or
-up 2 feet, 90 degree elbow and 15 feet out gable end which is parallel to prevailing winds.
My inclination is to leave the roof undisturbed and perhaps avoid force-fed cold air leaking past the damper. Good plan or not?
Climate zone 4a, NJ
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Replies
Without knowing more, I tend to want to see such penetrations made through walls rather than roofs. The less holes in a roof the better, in my humble opinion, especially a low pitched roof. Perhaps I am daft but usually kitchens have a window which usually means they are often bounded by at least one outside wall. Is the range/cooktop on some island far from the outer wall? However I think it isn't uncommon for those ducts to travel that distance.
Peter,
Through the wall is better. If the horizontal duct has to travel through a vented unconditioned attic, make sure that the duct is very well insulated.
Thanks very much for the guidance, guys. Joe, yes, it is an island hood. Martin, I'll pile on the insulation; thanks for mentioning it.
Go out through the wall. You can get much better backdraft dampers for wall applications.
Thanks, David. Any recommendations? I just ordered a Broan damped wall vent cap, but it's not too late to zig.
Seiho makes the best I have found.
Thanks for the tip, David.