“Easy Open” packages. The kind with enough hot glue on them to glue a battleship to the wall. When you finally get into them, the box top is shredded so much they’ll never close again, especially if the contents should be kept fresh.
If you think about the order of installs - and placement/replacement of a cabinet later - you wooldnt want it attached to the in-wall vents by much if anything - if the cabinet is well made, the channel thru the bottom of it to the external vent will be sufficient.
This assumes that the register is at the bottom of the cabinet and not into the big open space - theres usually only about 3" of space there - and it should be reasonably sealed.
Yes, this is how mine is designed. The base of the cabinet is about the height of a 2x4, and seems to be completely sealed from the rest of the cabinet.
J.
I had something like this, but it was the air return channel which used a sealed off wall space (Sheetrock and 2x4’s sides) and there were 2 intake vents. The upper near the ceiling and the lower near the floor.
It was intentionally done this way when central a/c was installed and retrofitted into the current vent system. In the summer the lower very is sealed off and in the winter the upper one is. It does seem to work well, or at least it did when I lived there.
My bathroom is set up the same way as the OP’s. Everything in this house is shoddy.
But, I get plenty of hot air from that register. And it sure made things easy the couple of times I had to have the vanity removed and replaced. I thought “Huh!” the first time I realized how it was set up, too, but really I have no complaints about it.
I am a little confused and not thrilled with the “no caulk tub surround.” There is to be no caulk in the seams, which I didn’t realize when I decided to caulk it. Then I had to pull the caulk out and now I think I’ve messed up the water flow and it flows into my drywall at one point. Plus it traps mold. Sigh.