If you want to make your house more energy efficient, the first thing to do is stop air leaks. Because drywall is great at stopping air, it can be part of a house's air barrier when installed using the airtight-drywall approach. This approach, described in this article by longtime Fine Homebuilding contributor Myron R. Ferguson, makes use of caulks, sealants, canned foam, and gaskets to seal the seams between sheets and to stop airflow through holes cut in the drywall. Ferguson begins an airtight-drywall job by applying flexible caulk to all gaps in the framing and by sealing electrical boxes. He then hangs the ceiling, making sure to seal the holes he cuts out for junction boxes and light fixtures with caulk, and to seal the perimeter between the framing and the drywall with canned foam. Finally, he hangs the walls. Window openings are sealed with caulk and polyurethane construction adhesive, large gaps with canned foam, and small gaps with caulk. Ferguson demonstrated his technique at FHB's Project House, and this article includes a drawing that shows the exact locations where he applied caulk, foam, and construction adhesive.