Exterior air infiltration and interior air exfiltration occurs through electrical boxes in exterior walls and ceilings. Warm air exfiltration can carry water vapor that can condense in the wall and/or attic cavity leading to rotting and mold growth - as well as increasing the heating load during the heating season. This air vapor barrier box is designed to attach to a wall or ceiling frame member and can contain up to three conventional electrical boxes. Once installed, use silicon sealant or low expansion foam to seal the box where the wires pass through into the wall cavity and tape the vapor barrier to the box flange with contractor's sheathing tape. This will eliminate the passage of air and moisture through electrical boxes. The interior of each box is 6.5 inches x 7.5 inches x 2.9 inches deep, and this model has LESSCO's new patented hinge feature.