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Final Certifications

The most important reason for certifying the energy performance of a home is to clearly communicate the value of the home’s added features to the marketplace. Certification supports the home’s higher appraised value and encourages higher levels of financing to cover the cost of energy improvements. In a rental market, certification can make the case for higher rents. While the financial benefits of living in a zero energy home are clear, real estate professionals (brokers, appraisers and lenders) are just beginning to embrace the additional market value offered by zero home certification. Third-party certification is an important way to verify that the home is a genuine net zero home under normal use conditions.

The energy analysis used in most certification methods is based on the energy consumption of average families, so even if a home is certified as a net zero energy home, it may not reach zero energy performance if residents have above average energy consumption habits. Just as the MPG rating on a car cannot guarantee that drivers with poor driving habits will get the rated fuel efficiency, neither can zero energy certification guarantee that a home will achieve net zero energy consumption for residents whose energy use habits are above average. Nonetheless, zero net energy certification gives all stakeholders reliable information that the home’s energy performance and financial returns will benefit its occupants and that it will be a zero energy home with average, or below average, energy use by its residents.

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Rating Energy Performance Is The Heart of Zero Home Certification
Rating a home’s energy efficiency performance is essential to certifying that a home is a zero energy home. If a home’s energy performance is rated at, or very close to, zero then the home is presumed to be a zero energy home. There are two common energy efficiency rating systems in the U.S.: the HERS rating system and the Energy Performance Score.ter should also check the home for potential carbon monoxide emissions from natural gas appliances.
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Energy Performance Scores – EPS Scores
Energy Performance Score – EPS score – developed by the Energy Trust of Oregon, estimates the actual energy use of the building. With EPS, lower scores mean more efficient homes and lower carbon emissions. The score can range from zero to over 200, with zero being the best possible rating. Compared to the HERS rating, the EPS score estimates actual energy consumption, accounts for actual house size, allows for home-to-home comparisons, and estimates total carbon emissions. Computer modeling and field inspections are similar to the HERS process.
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Home Energy Rating System – HERS Index
The most common home energy efficiency rating in the U.S. is the Home Energy Rating System (HERS) Index, which generates a HERS Index Score. The HERS analysis consists of diagnostic testing conducted with a blower door test, a duct leakage tester, and visual inspection. These tests determine the amount and location of air leaks in the building envelope, the amount of leakage from HVAC distribution ducts, and the effectiveness of insulation inside walls and ceilings. In new construction, a HERS score is estimated from the plans. During construction, the HERS rater visits the site two or three times to ensure that energy measures are properly installed, and occasionally to facilitate blower-door directed air sealing. The final rating is given when construction is complete. The data resulting from a home energy analysis is compared to a “reference home” – a home of the same size and shape – so the HERS Index Score is relative to the size, shape and type of house that is being rated. The lower the number, the more energy efficient the home relative to the reference home. Under most circumstances a HERS rating of zero can be used to certify that a home is truly a net zero home, although there are some challenges with this system. According to Bruce Sullivan, of BaseZero, LLC, the HERS rating system has several limitations. The HERS index indicates energy efficiency relative to a HERS reference home, but it does not factor in the size of the house. Neither does it allow direct comparisons between homes, nor does it reflect actual energy use and carbon emissions.

Several organizations offer formal net zero energy certification programs
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Earth Advantage provides Zero Energy and Zero Ready Home Certifications in locations where Earth Advantage green certification is offered.
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Built Green's Net Zero Energy Label indicates that a home is modeled to reach zero energy.
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The Living Building Challenge offers nationwide Net Zero Energy Building Certification.
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The Green Built Alliance certifies zero energy homes through their Green Built Homes program.
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Passive House Institute offers nationwide Passive House Certification.
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The Green Home Institute acknowledges homes through the Zero Energy Capable Program
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The Department of Energy has a Zero Energy Ready Certification.
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The U.S. Green Building Council offers LEED Zero to compliment their other green building certifications.
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The Canadian Home Builders Association launched a Net Zero Energy Home Labeling
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Program that recognizes homes that reach zero energy ready status too.

If you are building a zero energy home, use one of these programs to certify that the home you have built has reached the zero-energy standard. And if you are purchasing a zero energy home, look for one of these certifications to ensure that the house you are purchasing is a genuine zero energy home.