Zero Energy Buildings
Source: US Department of Energy

The U.S. Department of Energy's Zero Energy Homes research initiative is bringing a new concept to homebuilders across the United States. A Zero Energy Home (ZEH) combines state-of-the-art, energy-efficient construction and appliances with commercially available renewable energy systems such as solar water heating and solar electricity. This combination can result in net zero energy consumption. A ZEH, like most houses, is connected to the utility grid, but can be designed and constructed to produce as much energy as it consumes on an annual basis. With its reduced energy needs and renewable energy systems, a ZEH can, over the course of a year, give back as much energy to the utility as it takes.

Only about 10% of new homes in the United States are built significantly above the minimum efficiency standards. Homes now use more total nonrenewable energy than ever before. In fact, buildings currently consume more than one third of all the energy and two thirds of all the electricity used in the United States. New single-family homes are, on average, larger than ever before, employ many more electrical devices, and 50% are being built in the Sunbelt where the need for electricity is intense because of summertime air-conditioning loads.

The Department of Energy (DOE) is sponsoring the Zero Energy Homes initiative to capitalize on the expertise and technology that already exists within DOE and its industry partners to dramatically reduce the amount of energy consumed by single-family homes. The ZEH initiative seeks to build more and more homes that perform at least 50% more efficiently than those built to current minimum efficiency standards while also increasing the number of new homes that can meet their own energy needs. The ultimate goal of the ZEH initiative is to bring the benefits of zero energy technology into the mainstream of both the residential and commercial building industries, but the initiative's near-term focus is on new home construction.

Zero Energy Homes have a number of advantages:

• Improved comfort—an energy-efficient building envelope reduces temperature fluctuations.
• Reliability—a ZEH can be designed to continue functioning even during blackouts.
• Security—a home that produces energy protects its owner from fluctuations in energy prices.
• Environmental sustainability—a ZEH saves energy and reduces pollution.

Zero Energy Homes optimize a variety of features:

• Climate-specific design
• Passive solar heating and cooling
• Natural daylighting
• Energy-efficient construction
• Energy-efficient appliances and lighting
• Solar thermal and solar electric systems.