Bonus Room Blocking and Air Barriers
It is very important to get the blocking and air barrier installation correct on rooms above garage. Improper installation is one of the leading causes of comfort issues, frozen pipes and energy loss from a room above garage (it is most likely not an HVAC issue like typically thought). As you can see in the diagram above, there needs to be blocking between unconditioned and conditioned space in the joists, continuous top and bottom plates (properly sealed) and a properly installed air barrier (see below) on the attic side of the walls.
How to Properly Install an Air Barrier
For an Air Barrier to work, it has to be installed properly. With a poor install, it will not stop air from passing through. When installing an air barrier, it should be cut around any framing or obstacles, all seams sealed with tape, caulk, or other air sealants and it should be help up with cap nails or cap staples (if regular nails or staples are being used, then the heads of each one need to be sealed just like the seams).
Grade 1 vs Grade 3 Insulation Install
Proper Duct Sealing for Total Testing
For an HVAC System to perform as designed, it must be sealed properly. All factory seams and connections, floor penetrations, and framing members must be sealed. This includes the Cabinet, Coil, Trunk, Plenum, and Filter Slot. Sealing can be done with a variety of products such as; Mastic, Caulk, Tape, and various others. A properly sealed HVAC system will increase overall efficiency and comfort.