The entire box is insulated with rigid foam, which makes it energy efficient—once the foam was installed, the heat mat only needed to turn on about a quarter of the time. To give it a more ...

Closed-cell polyurethane spray foam has some pretty awesome qualities. It has a high R-value. Its resistant to water, mold and insects. It expands into hard-to-reach nooks and crannies. Heck, it ...