I just replaced a microwave oven in the kitchen and all went well. I told my wife I wanted to make sure it was venting well so I started to climb on the house to "see"/ "hear"/ "feel" how it was venting/ exhausting from the kitchen. My wife told me that there was no vent that went outside thru the roof-- and she was right. She said the vent was in the attic and again, she was right. Anyway, I went into the attic and saw a nice vent line going from over the microwave up to but not out of the roof. From where I viewed did not see any inside openings on the vent plimbing-- although I did not climb over to the vent and look on the "backside". My question is: should the exhaust vent plumbing be "vented" inside the attic--- ie should there be holes or luvers or a flapper opening where the exhaust fume can escape into the attic? Any replies to this question would be appreciated. I am an older gentelman; but still capable of getting around pretty good.