I'm looking for something, I have no idea what, but maybe someone here will help me find it.

A few years ago I did a kitchen remodel that entailed moving the sink across the room. Now the sink has a window, and the relationship is great. When the remodel was done, the plumber ran a new vent up the wall. When he got up to the ceiling, instead of going through the header, he came into the room in the corner, went up into the crawl space and through the roof (it's in the corner of a Cape house). The corner cabinet has an angled back side, so the vent is in a happy place and all is good.

Here's my issue. When the cold winter months arrive, the vent transfers the cold air into the room. If you hold you hand in the corner of the counter top, you can feel the cold air drifting down from the back angled corner of the cabinet. I have tucked insulation into the open space behind the cabinet, and it helps, but I would like more. Open the cabinet door, and an avalanche of cold comes to greet you.

So, I'm looking for something, but I have no clue what it is that may help. One thought that I have is to put a cap/cover on the end of the vent up on the roof. My thinking is that it would prevent the vent air from the turbulence of the outside world, and maybe my kitchen would be less cold/drafty. Before I do that, I figured I would post here so that I can be told that it won't work, but here's what will: ___________________ . I hope someone can fill in the blank for me.

Thanks in advance,
Ray