Foam insulation block by EnergyBlock
The EnergyBlock is a simple, inexpensive block of foam insulation, specifically molded to fit perfectly around standard electrical boxes. It seals around and behind every electrical box that essentially eliminates air infiltration in both directions. What sets the product apart is that most energy efficiency products that claim to seal electrical boxes have a problem sealing the wire where it enters the box. It is sealed after rough wiring is complete so there is no chance of breaking the seal. Another aspect of the product is that it provides a solid R-10 insulation behind the outlet everytime, also reducing chance of mold forming due to moist inside air escaping and condensing on an exterior wall.