Hello, I recently purchased a 1920's house with the original cast iron sinks in both the first floor bathroom and kitchen. We are replacing them with the modern sink/cabinet units, however in the bathroom the heat vent is one of those old huge square ones, and the corner of the bathroom cabinet overlaps with the vent. Also, the bathroom ends up warmer than most of the house and is across the hall from the thermostat. I haven't tried my hand at any duct work before, though we did do other projects including tiling the shower. Would it be possible to fit a more modern, smaller vent into the wall or would that screw up the air flow? I wouldn't mind if the bathroom was a bit cooler, that would actually be good. How hard would it be to shift the vent over a couple inches so the two don't over lap? If it helps its a first floor bathroom over an unfinished basement, and the wall is partly torn out already for plumbing work. Thanks!!

I am just finishing up the last of a year and a half basement finishing project and down to the last details. I have built in the mechanical room area that holds the hvac system. There is a bedroom (120 sq ft.) and a theater room (200 sq ft) that adjoins the mechanical room. The system takes care of the entire first floor and basement area of the home, about 2700 sq. ft. Secondary heat pump handles the second floor area. I panned in a stud bay in each room that adjoined the cold air return ducting to make it easier to connect to the return system. The mechanical room has shrunk quite a bit down to 120 sq. ft. The area is pretty well sealed off from the rest of the basement. I put a short door in intending to give some area under the door to pull combustion air. However, the carpet we picked with the pad closed that off. My question is do I have enough sq. ft. for combustion air? If not could I fix this by just putting a return air grill on the other side of the panned stud and not hook up to the cold air return duct? Thus letting the air pushed out of those two rooms into the mechanical air for combustion? Thanks in advance for all replies.