In June of last year, Meritage Homes began selling homes in a community called Lyon’s Gate, in a suburb of Phoenix, Arizona. The marketing pitch for the eight models available in the development was that they were the first generation of Meritage houses to achieve Home Energy Rating System (HERS) scores in the 20s and low 30s – far superior energy performance ratings than, say, the 85 HERS points required for an Energy Star rating.

Since then, Meritage, the nation’s tenth largest publicly traded production builder, has begun selling homes with similar energy efficiency features in other communities and used the HERS Index to calculate their projected performance. Last week, Residential Energy Services Network (RESNET), the national association of home energy raters that developed the HERS Index, announced that it entered into a memorandum of understanding with Meritage that includes the homebuilder’s commitment to having its homes’ energy performance evaluated by RESNET-certified raters, and to marketing the homes with energy performance labels featuring the HERS scores.

“This will clearly differentiate homes built by Meritage Homes and put competitive pressure on the new home industry to follow suit. It is expected that this agreement will serve as a model to other large production builders that would have positive outcomes for consumers, RESNET, and the new-home industry,” RESNET said in a news release.

Homes in Meritage’s Lyon’s Gate development are offered in eight models ranging in size from 1,640 sq. ft. to 3,062 sq. ft. and in price from $176,900 to $231,900. Each includes an Echo photovoltaic and solar thermal system, spray foam insulation in the exterior walls and roof, high-performance windows, water efficient plumbing, and a 14 SEER air-conditioning unit.

Casting the RESNET net

RESNET’s alliance with Meritage is but one of many the rating group has indicated it intends to forge with builders. In February, production builder KB Home announced that the marketing of each of its homes would include an Energy Performance Guide – essentially a sticker that shows the average monthly energy cost of operating the home, which is calculated using the HERS Index rating of the building, based on an analysis of its design, and on local utility rates.

The HERS Index uses as its reference a comparable home built to the specifications of the 2006 International Energy Conservation Code. Such a home would have a HERS rating of 100 – the reference point used for rating the performance of both older homes (which often score higher than 100 because they tend to be less energy efficient) and new homes. HERS ratings factor in insulation levels in the shell, the performance of windows and their ratio to wall space, the solar orientation of the building, the efficiency of the HVAC system, and the airtightness of the building’s ductwork and envelope.

RESNET has not achieved total ubiquity. Other rating systems, including Earth Advantage Institute’s Energy Performance Score – which rates energy efficiency according to the MBTUs (million BTUs) a home uses annually and indicates estimated carbon emissions (in tons per year) as well as average annual energy costs for the house in question – have also gained traction among builders.

The HERS Index did, however, find a spot among performance evaluation criteria used by Passive House Institute U.S., through a recently announced an agreement that makes PHIUS an affiliate member of RESNET. The objectives of the agreement include adoption of rating standards and procedures “that harmonize with the RESNET provisions for Passive House certification, quality assurance, codes of ethics, and standards of practice.” The two organizations also agreed to adopt a uniform calculation of carbon savings for buildings built to the Passivhaus standard.