Steve writes from Kailua Kona, Hawaii: "Our engineer is demanding that we install the ceiling insulation in the top cord of the trusses opposed to the bottom cord against the gypsum drywall ceiling. We are opposed and feel that they will not get the full benefit of the insulation. The project is in Hawaii and the ceiling height is 9' above the finished floor and all of the rooms are air conditioned."

Answer: For the best performance, insulation should surround the living space. If not, you will be conditioning the unused 9 ft area.