According to a recent article in Builder magazine, the Home Energy Rating System (HERS) developed by the Residential Energy Services Network (RESNET) has become the closest thing to a national building standard gauging home performance, as builders compete not only with each other but against a large inventory of existing homes often sold for less than replacement value.
Claire Easley’s article reports that RESNET has entered into agreements with 20 of the country’s largest home builders, including KB Home, PulteGroup, and David Weekley, to have their homes rated by HERS. The trend suggests a roll for raters in future codes that may require more stringent verification of envelope and HVAC performance. Current code assumes installations are defect free and in compliance with manufacturers’ recommendations, verified through a handful of quick inspections to check for only the most egregious structural mistakes.
As Vision 2020 Chair Sam Rashkin, chief architect of the DOE’s Building Technologies Program, pointed out during a recent Vision 2020 program conference call, “It’s not just pushing higher levels of windows and insulation, but rather getting this stuff done right.” So the envelope detailing, insulation, window, and HVAC installation actually meet code, rather than just the materials meeting code. Testing provides verification of materials and workmanship meeting the minimum standard of quality and care required by evolving energy codes. In this one area, every rating system has surpassed code, not just in material specifications, but affording consumers a reasonable, third-party assurance of installation quality.
Massachusetts has already implemented a HERS requirement in its 2010 "stretch code." New homes built under the stretch code must get a HERS rating. Renovations and additions to homes have the option of the HERS rating or a “prescriptive” approach, whereby specific efficiency measures are required, but no computer modeling is done.
Following Massachusetts’ example, and that of cities such as Boulder, Colo., Austin, Texas, Santa Fe, N.M., Santa Barbara, Calif., and others, a simple performance measure, such as a HERS score, may be an important step toward a national energy standard for residential construction, which can be applied to new construction by code, and existing housing by choice.