How to Recognize a “High Performance Home”

Two homes appear outwardly identical, but one home is described as a “high performance home”. How can you recognize when the “high performance” claim is justified? The answer to that question is found in the aphorism, “You can’t judge a book by its cover.” It’s what is inside that counts.


Perhaps the easiest measure of a high performance home is whether the home is third-party certified as meeting one of several nationally recognized green building standards. For residential construction, those voluntary national standards include:

• Energy Star certification through the U.S. Environmental Protection Agency (EPA),
• Builder Challenge certification through the U.S. Department of Energy (DOE)
• U.S. Green Building Standard, which is the only ANSI-approved national green standard
• LEED for Homes certification through the U.S. Green Building Council.

EPA’s Energy Star and DOE’s Builder Challenge program concern themselves primarily with whole-house energy efficiency. An Energy Star home must be tested and verified that it is built to be at least 15% more energy efficient than the same home built to current International Energy Conservation Code (IECC) standards. For certification under the Builder Challenge program the energy efficiency bar is raised, requiring that a home must be tested and verified to reflect energy efficiency that is at least 30% greater than the same home built to current IECC standards.

Representing more broadly defined green building standards, both the U.S. Green Building Standard and LEED for Homes encompass independently certified energy efficient construction and verify higher standards for water conservation, indoor air quality, environmental site design, sustainable building practices and consumer education.

Each program includes a verifiable aspect of energy efficient construction among its threshold criteria for green certification, implicitly recognizing that this is the single most important and compelling aspect of green building for most prospective home buyers. For each national standard the same frame of reference is used to reflect the extent of a home’s energy efficiency as compared to a new home constructed to current IECC standards. That frame of reference is a nationally accepted HERS Index calculated by persons trained and certified in those aspects of building science affecting a home’s energy performance. HERS stands for Home Energy Rating System. A HERS Index of 100 reflects a new home built to the standards of the currently adopted energy conservation code. A home built to energy efficiency standards that exceed the adopted energy code will have a calculated index that is less than 100. The difference between a home’s calculated index and 100 represents the percentage by which the home is more energy efficient than a home built to current energy code standards. Thus, a home that is certified as meeting Energy Star or Builder Challenge standards, the HERS Index for the Energy Star home must be 85 or lower and for the Builder Challenge home 70 or lower.

A future blog post will identify tests that a certified HERS rater will apply in calculating a home’s HERS Index and will address other objective standards used to gauge water conservation and indoor air quality. For now, though, it is important to understand that the starting point for a high performance home is one independently certified by a qualified HERS rater as meeting at least Energy Star standards and that a home with the lowest HERS Index will be the highest performance with respect to energy efficiency.