This retrofit house is located in Jamaica Plain, MA (Cold Climate). It involved adding 1” foil-faced polyisocyanurate rigid insulation and closed-cell spray foam insulation below the roof deck. The walls were retrofitted to add two 2” layers of polyisocyanurate rigid insulation to the exterior of the existing wall sheathing and blown-in cellulose insulation to the existing 2x4 walls. Closed-cell spray foam insulation was added to the interior of the rim joist and foundation wall, and also over the existing slab.
For complete details on this deep energy retrofit, go to
National Grid Deep Energy Retrofit Pilot Program–Comprehensive DER of Three-Family Triple Decker