When you hear the words, net zero energy home, a few ideas automatically pop into your head. Right?
But what does it really mean?
For the best answer, we turned to the Net Zero Energy Home Coalition, which defines a net zero energy home as one that produces at least as much energy on site from a renewable source as it uses on an annual basis. These super-extreme-energy-efficient homes balance their energy needs with the use of renewable technologies. In terms of energy, it's a home that sustains itself.
You'll find that there are different degrees of these net zero homes and buildings around the world. Some buildings even supply a surplus of energy while others consume a bit more energy than they produce. These “near-zero energy buildings” or “ultra-low energy houses” are all a part of the green movement that is sweeping the world as we strive to slow, and hopefully diminish the use of our limited supply of fossil fuels. Of course, we hear all the time about new energy efficient and green homes as the new norm in home building in Idaho, but a home that can entirely sustain itself? A home that requires no utility bills? Sign me up!
It might seem more like science fiction now, but net zero energy homes and buildings are gaining momentum as they gain more and more popularity. Plus, the zero-energy goal is becoming more attainable as the price of alternative energy technologies goes down while the price of traditional fossil fuel goes up.
Late last year, the National Institute of Standards and Technology, as part of an effort to establish energy standards and ideal practices for net zero energy homes, completed a prototype of a net zero energy home in the city of Gaithersburg, MD, just outside of Washington.
What's the Functionality for the Bottom Dollar?
The cost of the house reached $2.5 million, mostly due to the costly monitoring equipment.
The house looks a lot like a typical luxury home nearby, except that it's anything but. The 4,000 square foot residential test facility hosts a simulated family of four and closely monitors how the house operates. The home is so energy efficient that over the year, it is expected to produce as much energy as it needs.
Sensors and computer programs simulate those living in the house day by day as actual humans would. Theyl move from room to room, turn on and use appliances, cook, take showers and baths. Small devices are setup to simulate the heat and humidity that actual human beings would produce in the two-story, four-bedroom house.
The lab is used to test various high-efficiency and alternative energy systems, materials, and designs.
Inquisition and its Results
The researchers in Gaithersburg hope to demonstrate that a net zero energy house can fully function in any neighborhood. The research will take place over the course of a year, and the home is used to test existing as well as new energy efficient technologies. The goal is to develop new methods of test that more accurately reflect how those technologies will perform in a real home rather than a simulated environment.
In fact, net zero energy buildings are more common than you may have assumed. According to the New Buildings Institute and the Zero Energy Commercial Building Consortium, at least 21 commercial buildings in the Unites States meet net zero standards. These buildings fall anywhere between office buildings, schools, and libraries. There are more buildings out there that would classify if they installed more on-site renewable energy systems. Plus, there are dozens more in the works.
The movement toward net zero energy buildings is taking further hold with an Executive Order titled Federal Leadership in Environmental, Energy, and Economic Performance that the President issued back in late 2009. It mandates that at least 15 percent of existing federal buildings and leases meet Energy Efficiency Guiding Principles by 2015, and that progress continue to be made toward 100 percent conformance of all federal buildings, with an eventual goal of 100 percent achieving zero net energy by 2030.
They've got their work cut out for them. The U.S. government consumes more energy than anyone else in America with about 500,000 buildings. According to the mandate, this means that 75,000 buildings must meet these guiding principles in two years.
No. 1 Design for Zero Net.
No. 2 Super seal the envelope. This phase begins with an air-tightness standard of 0.6 to 1.5 ACH at 50 Pascals. It gets more and more fanatical from there. This envelope is a formidable barrier which air doesn't stand a chance against.
No. 3 Super insulate. It speaks for itself.
No. 4 Minimize Thermal Bridging. They suggest using a Thermal Enclosure Checklist Guidebook to help you with this one.
No. 5 Use Highly Insulated Windows and Doors. You're gonna need the best of the best with the most advanced windows and doors to create tight air seals. Use triple-pane windows strategically placed where the common living areas are located.
No. 6 The Sun Should Significantly Contribute to Heating. This gets fairly complicated.
No. 7 Also use the Sun for Hot Water. They suggest using Solar Hot Water with electric back-up.
No. 8 And Again, use the Sun for Electricity. Of course, Solar Photovoltaic Panels are a must for any energy zero home.
No. 9 Create an Energy Efficient Fresh Air Supply. A highly efficient Energy Recovery Ventilation or Heat Recovery Ventilation system is a must.
No. 10 Energy Efficient Heating and Cooling.
No. 11 Energy Efficient Lighting and Appliances.
No. 12 Use Energy Modeling.
Are zero energy homes the future in commercial and residential real estate? With zero energy bills and zero carbon emissions and increasing affordability, we're getting closer and closer to that reality.
Scientific American: Net Zero Energy Buildings Take Hold in U.S.
Net Zero Energy Home Coalition: http://netzeroenergycoalition.com/