Buildings account for about 40% of national energy consumption, 70% of electricity consumption, and nearly half of all greenhouse gas emissions annually in the U.S. ZETA's zero energy homes provide one of the first nationally scalable solutions to these unsustainable environmental impacts. Using a whole-systems design approach, high performance materials, and an innovative mechanical core, ZETA homes require 40%-60% less energy overall and 65% less energy for heating, cooling, and hot water than a comparable structure (based on data published by ZETA's partner: U.S. Department of Energy's Building America program). To achieve net zero energy, ZETA homes use grid-tied photovoltaic systems and other clean energy sources.