I'm looking to punch some holes in my pine ceiling in my family room through to the master bedroom (which has ugly low pile carpet) to allow the warm air from the woodstove to take the chill off of the bedroom. The old section of our house has a version of these, and they help keep the bedroom on that side of the house much warmer. http://www.wayfair.com/Minuteman-International-Cast-Iron-Register-with-Louvers-JR-14-XMM1096.html I think I'd need 2 pieces, a register and a grate? how do I seal off the box so that I'm not heating into the ceiling/floor but rather just opening a short tunnel between the 2 rooms? Thanks!