While I have noted some zero energy homes (ZEH) being built, I have not seen any projections of their market penetration or potential energy savings prior to this article.
“Zero energy homes are technically feasible today,” says the National Association of Home Builders in its study, ‘The Potential Impact of ZEH.’
“If cost trends continue and research milestones are accomplished in solar energy and efficiency technologies, ZEH will eventually become economically competitive with conventional construction when utility costs are included in the cost of home ownership,” it notes. ZEHs could be moving into the mainstream housing market as early as 2012 and could reduce energy consumption among all single-family homes by 19% by 2050, even as more than one million new homes are added each year.
As the cost of solar PV systems declines and PV production increases 30% a year, “the market penetration of these highly-efficient homes has already begun and will continue in selected markets,” the study notes. ZEH will get a further push from low-cost solar thermal water heating designs under development now, complementing the portfolio of energy-efficiency improvements in appliances, building envelopes, windows and mechanical systems that is also moving into the market.
Zero energy homes are connected to the grid, and combine energy-efficient design and technology with solar electric and thermal systems to produce as much energy as they use on an annual basis, resulting in net zero energy consumption. The first ZEH in the U.S. was built in Arizona in 2003.