According to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), more than 30-percent energy savings can be achieved using the recently published ANSI/ASHRAE/IES Standard 90.1-2010, Energy Standard for Buildings Except Low-Rise Residential Buildings, vs. the 2004 version.

ASHRAE made the announcement upon receiving the final analysis from Pacific Northwest National Laboratory in support of the U.S. Department of Energy (DOE) Building Energy Codes Program on addenda included in the standard. Sixteen different building prototypes were modeled in 17 different climate zones for a total of 272 building types and climate zone combinations.

“Three years ago, the 90.1 project committee set an aggressive goal of 30-percent savings for the 2010 version,” ASHRAE President Lynn G. Bellenger said.

Without plug loads, site-energy savings is 32.6 percent and energy-cost savings is 30.1 percent. Including plug loads, site-energy savings is estimated at 25.5 percent and energy-cost savings at 24 percent. On a nationally aggregated level, building-type energy savings ranged from 8.8 percent to 38.3 percent and energy-cost savings from 7.9 percent to 33.6 percent. These figures include energy use and cost from plug loads.

The energy reduction was achieved by adjusting the following areas:

  • Scope: The scope was expanded so that Standard 90.1 covers receptacles and process loads, including data centers. This allows future addenda to address energy-consuming equipment and systems previously outside its scope.
  • Building envelope: Continuous-air-barrier and cool/high-albedo-roof requirements were added.
  • Lighting: Most interior lighting power densities were lowered, and additional occupant sensing controls and mandatory daylighting requirements were added for specific spaces, along with a new five-zone exterior lighting-power-density table.
  • Mechanical: Most equipment efficiencies are higher, energy recovery is required in more applications, economizers are required in more climates, and more energy-conserving controls are required.
  • Modeling: Modeling requirements have been clarified and expanded so building modelers can more accurately compare the energy costs of their building project with an appropriate baseline building as defined by the standard.

“The 90.1 standard is a fluid document,” Mick Schwedler, immediate past chair of the 90.1 committee, said. “As technology evolves, the project committee is continually considering new changes and proposing addenda for public review. The rigorous, open, public-review process following ASHRAE and American National Standards Institute (ANSI) procedures results in a document that is both technically sound and reaches consensus.”

The standard is written in mandatory code language and offers code bodies the opportunity to make an improvement in the energy efficiency of new buildings, additions, and major renovations.