Wall Oven and Microwave Vent to Attic

Question

I bought a house that has a microwave & wall oven combination. It's a Kenmore model from 2008. The microwave & wall oven combo vents through a metal pipe (about 4 inches) that runs through the cabinet above the unit and into the attic. Now I'm putting on a new roof and I have the chance to run this vent outside if I want to. Should I vent the microwave/oven unit outside through the roof or leave it venting into the attic?

As info, the cooktop and the range hood are on the opposite side of the kitchen, so I know those are not what is venting. The hot water tank and bathrooms are also not near the unit so I'm fairly certain it's the oven/microwave that's venting up.

I know that in general venting to the attic is a bad idea, especially for bathroom fans. However I was surprised that the oven/microwave was venting up to the attic at all instead of back into the room.

I have the chance to do this the right way since I'm putting on a new roof. It wouldn't be a problem to vent this through the roof, but I also don't want to put on unnecessary roof vents.

Can anyone help?

Answer 1

I am in the appliance repair business. I have never seen a Whirlpool oven and microwave that are vented. The only brand of wall oven that I ever saw vented was an older Thermador.

If it is coming from your oven/microwave combo, it would be vented out the top and you should be able to see that in a false cabinet above the unit.

They used to vent the old Wedgewood stoves with a 4 inch vent. I'm wondering if it is an aol vent left over from the original kitchen. These old vents were always run up through the studs, the vents from the wall ovens that I have experience with were not run up between the wall studs.

Crawl back up in the attic and take a look at where this vent is coming from. If it is coming from between the studs, it is most likely an abandoned vent.