Tuesday, August 18, 2009

Energy Star rating for homes undergoing changes

The Energy Star rating for homes has long been a basic standard for consumers looking for energy efficiency, but as building codes have improved, the current guideline is starting to show its age.

One of the primary measures to get the Energy Star rating is the Home Energy Rating Standard (HERS). The HERS rating system by itself can be a strong indicator of how energy efficient a home is by providing a numeric indicator of energy performance. Although the overall process is a bit more complex, in our area a HERS rating of 85 or less is the basic measure for receiving the Energy Star label.

As defined now, most builders are very close or even surpassing the required rating guidelines simply by following local building codes and international standards. Since the Energy Star standard is supposed to identify those that exceed the norm by at least 15%, it is in danger of no longer achieving its defined purpose. In the meantime, other more comprehensive guidelines such as LEED and NAHB Green have achieved recognition for higher standards of performance.

The comment period for the new proposed guidelines closed on July 10th and will likely prompt at least some changes, but some of the more significant updates may include:
  • Indirect energy measures. Factors such as water usage and indoor air quality will be evaluated (already included in standards like LEED).
  • House size consideration. Under the current standard, larger homes get an advantage over smaller homes in the evaluation and thus obtain qualification easier.
  • Cost effectiveness policy. Inclusion of certain efficiency measures will attempt to ensure that improvements pay for themselves when included in a mortgage.
  • Application of State codes. Where state codes are more restrictive, they will be used as a baseline measure.
The Energy Star label has a distinct advantage of being widely known by the public as a measure of efficiency. If nothing else, the fact that the bar will be raised in 2011 is solid evidence that building science has gone through significant advancements in improving energy efficiency. We should expect to see that translated into continuing methods for lowering everyone's utility bills.

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