More homes may soon be energy-free. Homes and commercial buildings consume 40 percent of all energy used in the U.S., but the growth of net-zero homes could drastically curtail that. The Zero Energy Ready Homes—those that make the energy they use—are becoming more of a reality.In 2017, 8,547 units of net-zero housing or zero-already housing had been built in the U.S. About 38,863 were under construction, according to the Net-Zero Energy Coali