Constructing a building to the requirements in the 2013 version of ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, can result in 6- to 8-percent greater efficiency than constructing the same building to the requirements in the 2010 version, an energy-savings analysis performed by Pacific Northwest National Laboratory reveals.
Conducted in support of the U.S. Department of Energy’s Building Energy Codes Program, the analysis of 110 addenda included in the standard shows site and energy-cost savings of 37.7 percent and 37.8 percent, respectively, with the 2004 version of the standard used as the baseline for regulated loads only. For whole-building energy consumption, national aggregated site energy savings are 29.5 percent, while energy-cost savings are 29.0 percent.
On a nationally aggregated level, building-type energy savings range from 19.3 percent to 51.9 percent, while energy-cost savings range from 18.6 percent to 50.6 percent. These figures include energy use and cost from whole-building energy consumption, including plug and process loads.
Sixteen building prototypes were modeled in 17 climate locations for a total of 272 combinations of building type and climate zone.
The energy reduction was achieved through 33 addenda, the most significant concerning:
• Building envelope—opaque elements and fenestration requirements were revised to increase stringency while maintaining a reasonable level of cost-effectiveness.
• Lighting—daylighting and daylighting-control requirements, space-by-space lighting-power density limits, and thresholds for toplighting were modified.
• Mechanical—efficiencies for heat pumps, packaged terminal air conditioners, single packaged vertical heat pumps, air conditioners, and evaporative condensers were increased. Also, fan-efficiency requirements were introduced. Additional provisions address commercial refrigeration equipment, controls on heat-rejection and boiler equipment, requirements for expanded use of energy recovery, small-motor efficiencies, and fan-power control and credits. Revision-control requirements were added for many applications.
Another important change concerns the development of an alternate compliance path for computer-room systems.