Two architects have come up with an inexpensive way of air-sealing and insulating electrical boxes in exterior walls.
After puzzling over the best way of meeting a code requirement for sealed boxes, Bill Hicks and Lucas Schad developed a cardboard form called the Box Shell that wraps around an electrical box. The form is slightly larger than the box, creating a small gap on the sides and a space at the back that is filled with expanding foam to air-seal and insulate.
The Box Shell is installed after wiring has been roughed in and before cavity insulation is placed in the wall. After drywall goes up, the installer inserts the nozzle of a can of expanding latex foam between the electrical box and the form and fills the gap around the box and the space behind it with foam. It’s the foam, not the box itself, that creates the seal.
The company offers the shells in three sizes — for single, double and triple junction boxes — all under $2 a pop.
Schad and Hicks both work for LTS Architecture, Schad in Livingston, Montana, and Hicks in Minnesota.
Brie Braukmann, Box Shell’s product manager, said the pair was looking for a way to comply with a provision of the 2012 International Energy Conservation Code requiring sealed electrical boxes in exterior walls. Although there are other products on the market for sealing boxes, they are either more difficult to install, more expensive, or don’t provide as effective a seal, Braukmann said.
The company is very young. Braukmann joined the group in May, and in mid July the company was still waiting for its first shipment of factory-made boxes after exhausting its small supply of samples, some of them made by hand (the shipment has since arrived, and Box Shell’s website lists all three sizes for sale).
Box Shell hasn’t spent much on advertising so far and instead has been relying on word-of-mouth and social media. But the reaction among builders so far has been positive, especially when they know what the energy code requires.
“They’ve been really intrigued,” Braukmann said.
Get building science and energy efficiency advice, plus special offers, in your inbox.