Homes certified Energy Star after third-party verification tests passed

The number of homes built to Energy Star standards is on the rise, as more Las Vegas Valley builders realize the benefits of the program sponsored by the Environmental Protection Agency, according to representatives for a local coalition that promotes Energy Star home building.

An integral step in earning the Energy Star designation is verification of the home's energy efficiency by a third-party inspector.

The Energy Star label on a new home means that the home is at least 30 percent more efficient in heating, cooling and water heating than the national Model Energy Code, and that this performance level has been verified by a third-party energy rater.

Energy Star implementation and verification services are offered to home builders by independent companies known as Home Energy Rating System providers.

The first steps in a HERS rating involve the analysis of a home's construction plans. The rater reviews the construction drawings and specifications for energy-efficiency features including insulation, windows, space conditioning and water heating equipment, as well as procedures for sealing ducts and the building envelope.

The home energy rater uses this information to develop an energy analysis of the home. This analysis yields a proposed HERS rating for the house.

The HERS rating is a score between 0 and 100 with the Model Energy Code reference house assigned a score of 80. Each 5 percent reduction in energy use results in a one-point increase in the HERS score. Thus, an Energy Star home, which is required to be at least 30 percent more energy efficient, must score at least 86.

After construction, the third-party rater will verify the home was built to design specifications. This involves inspections to assess its performance, including conducting blower door and duct blaster tests. Results of the inspections and tests are entered into a computer simulation program to generate the HERS score.

The blower door test is a whole-house testing system that measures home envelope leakage. A large fan fits into an exterior doorway in a home and depressurizes the space inside the home, which then causes air to enter through any unsealed openings. This test quantifies conditioned air loss due to infiltration through windows, doors, cracks and penetrations.

The duct blaster tests leaks in the duct work, another way conditioned air is lost.

If the house performs at the level of HERS 86 or better, the third-party verifier will submit the home's rating information to the EPA and the home can be labeled as Energy Star. The builder must sign a partnership agreement with the EPA to do so.

If the residence fails to qualify, the reasons for the failure must be identified and corrected, and the home retested.

Real Estate home