Case study of a DOE Zero Energy Ready home in northern AZ that achieved a HERS score of 48 without PV or 25 if 3.5 kW PV were added. The two-story, 2,469-ft2 production home has 2x4 walls filled with R-13 open-cell spray foam plus 1-in. rigid foam over plywood sheathing, a sealed R-20 open-cell spray foam insulated attic, triple-pane windows, a 95% efficient gas furnace, and an ERV.