My boiler room is 8'x11' inside my attached garage. The inside is sheeted with 5/8" fire code sheetrock. I am enjoying the little bit of heat loss off the boiler and pipeing which is keeping my garage around 40 degrees. I was going to insulate the walls so I dont have to worry about freezing in the event of vacation,door open,power loss,etc,etc. Does anyone think i should not insulate? My garage is also insulated but very drafty around the doors.