Among the trickier areas to properly seal and insulate is around electrical boxes. These can often be sources of air leakage and are notoriously hard to properly insulate with batt products without excess compression. A new product, box shell, seeks to address both of these problems. As the site shows, the “shell” fits neatly around the electrical box, flush with the sheathing behind and affixed easily with a staple gun. From there, you can just cut a full notch out of a fiber glass batt and install it around the shell, then fill the area between the shell and the box with low expansion canned foam to seal it up. The company, still in its infancy, is offering single, double and triple junction box shells, all for under $2. Using these could help reduce concern that an evaluator, whether a building inspector or HERS rater, will ding you for problems around this typical trouble spot. A couple bucks for that peace of mind is probably worth it.
