Insulating Beyond the Code
The insulation that makes this FHB House energy efficient went way above and beyond code minimum.
Regarding insulation, the FHB House is definitely different from a code-built house. It is about 25% to 30% above the base requirement. We chose to hit R-20 under the slab, R-45 in the walls, and R-60 in the ceilings.
To insulate a house like this, you definitely have to pay attention to air-sealing. We used 15-mil poly on top of the insulation. We also used an air membrane to reduce air leakage through the wall.