My house was built in 1976. I recently replaced the range hood and discovered that the piece of rectangular ducting that runs inside the cabinet is not connected to the outlet vent on the outside of the house. It effectively vents into the attic space under the roof. That attic space is not used for anything, and in fact it is not even accessible.
My contractor quoted 650$ to install the duct, which is not surprising given the difficulty accessing that space.
What are the pros and cons to installing the duct vs. leaving it as is? Out of curiosity, was it considered a standard practice in the 70's to skip a 10-foot section of ducting and let the cooking fumes dissipate in an attic space?
Best Answer
Regardless of if this was ever standard, it's a bad idea. I lived in a 60's built house and the dryer vented under the house from a hole in the floor. The lint and moisture issues there were pretty bad to say the least.
The same issue is happening in your attic (crawlspace?). The moisture in the exhausted air can cause problems for sure. The air can also contain grease and other contaminants that will build up and cause... general grossness.
It's true that if you don't use the hood very much, it might not be a big deal, but if you want to to be done right, it needs to be in a duct from the hood, all the way until it exists the house through a wall or the roof.