The publication of the ANSI/ASHRAE/IES Standard 90.1-2013, Energy Standard for Buildings Except Low-Rise Residential Buildings, is bringing major changes to requirements regarding building envelope, lighting, mechanical, and energy cost sections.
"While many things have changed since the first version of Standard 90 was published in 1975, the need to reduce building energy use and cost has not," says Steve Skalko, chair of the committee that wrote the 2013 standard. "This standard represents many advances over the 2010 standard, as we worked toward our goal of making the standard 40 to 50 percent more stringent than the 2004 standard."
Opaque elements and fenestration requirements have been revised to increase stringency while maintaining a reasonable level of cost-effectiveness. These changes include:
- Criteria requiring double glazed fenestration in many climates.
- Minimum visible transmittance/solar heat gain coefficient (VT/SHGC) ratio to enable good daylighting with minimum solar gain, while not restricting triple- and quadruple-glazing.
- Simplification of the skylighting criteria.
These changes include improvements to daylighting and daylighting controls, space-by-space lighting power density limits, thresholds for toplighting and revised controls requirements and format.
Equipment efficiencies are increased for heat pumps, packaged terminal air conditioners, single package vertical heat pumps and air conditioners evaporative condensers. Also, fan efficiency requirements are introduced for the first time. Additional provisions address commercial refrigeration equipment, improved controls on heat rejection and boiler equipment, requirements for expanded use of energy recovery, small motor efficiencies and fan power control and credits. Control revision requirements have been added to the standard such as direct digital controls in many applications. Finally, the 2013 edition completes the work that was begun on equipment efficiencies for chillers in the 2010 edition.
Energy Cost Budget (ECB) and Modeling
Improvements were made to clarify the use of the prescriptive provisions when performing building energy use modeling. In addition, these sections were revised to enhance capturing daylighting when doing the modeling calculations.
More information can be found on ASHRAE's website.