A Retrofit for the Future
An old ranch gets an improved shell and strives for energy independence
Painting contractor Bob Ritacco and his wife dreamed for years of living in an energy-efficient house, but it wasn’t until they had spent 24 years in two poorly performing houses that they finally got their chance. They bought a small ranch in poor condition, intending to tear it down and build a new home until architect David Toder convinced them to do a deep-energy retrofit (DER) instead. This aligned well with Ritacco’s interest in zero-net-energy (ZNE) design. The remodel included an addition made with insulated concrete forms (ICFs). Ritacco adopted the Building Science Corporation’s standard for insulation in a cold climate. To create an R-60 roof, he built 11-1/2-in.-deep rafter bays, filled them with dense-pack cellulose, and then added 4 in. of rigid foam on the roof. To create R-40 walls in the addition, he added 1-1/2 in. of closed-cell spray foam to the outside of the ICFs; to do so in the existing house, he filled the stud bays with dense-pack cellulose, then added 4 in. of closed-cell spray foam to the outside. Spray foam on the cinder-block walls in the basement brought the foundation walls to R-27. In the addition, underslab rigid foam created an R-20 floor. Because he did not want to lose ceiling height in the existing basement, he used only 1-1/2 in. of rigid foam on top of the slab. Heating and cooling are provided by a Mitsubishi Mr. Slim ducted air-source heat pump, and PV panels on the roof supply most of the home’s electricity. In a sidebar, Ritacco discusses the merits of being his own general contractor on the project.