Does an undercut door or a transfer opening qualify as a permanent opening?
For example, it seems advisable to further define whether an undercut door or a transfer opening qualifies as a permanent opening between rooms, and if so, how large would it need to be, and how high or low it should be installed.
It is clear that some ASHRAE research would be helpful in better defining how to treat an undercut door or a transfer opening.
Clearly, undercut doors or transfer openings would eventually permit a large leak of refrigerant in one small room to disperse to adjacent rooms.
1 Undercut door
casing using underlayment and flooring as a guide.
Next, undercut door
casings by laying the blade of a handsaw on a scrap of underlayment and horizontally cutting off the bottom of the casing.
Closets need "active" returns at the ceilings and undercut doors
. Closets are now getting colder.
4 UNDERCUT doors
casings, jambs and other spots where you can't hide the flooring edge with baseboard or transition pieces.