Range ventilation and insulation
chrisjohnston2112
| Posted in General Questions on
I have a microwave over my oven/stove . The microwave is vented to the outside. Metal ductwork goes from the top of the microwave through a hole cut in the bottom of a cabinet above the microwave. The vent then goes through a hole cut in the back of the cabinet through the wall to the exterior. The total length of the metal ductwork exposed in the cabinet is about two feet. I noticed today the metal duct work in the cabinet is very cold (it’s winter), and the interior of the cabinet is cold. Is there any way to safely insulate this duct work?
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Replies
Hi Chris.
I don't think there are any safety concerns with insulating this ducting, if you can find a way to do it. That said, ducts within the building envelope are not typically insulated. You could also make sure that the backdraft damper is working, consider upgrading the backdraft damper, and make sure that air isn't leaking around the duct penetration. There are some backdraft damper recommendation from GBA Members to consider in this thread: https://www.greenbuildingadvisor.com/question/how-to-prevent-leakage-through-the-range-hood
I think that if you insulate that part of the duct it's not going to make a dramatic difference. You'll probably then notice, if you haven't already, that the microwave itself is quite cold. It's a pretty massive thermal bridge directly from the outside to the inside, all metal. Making sure it leaks as little as possible is the best thing you can do.