Environmental Performance Criteria 2.2
Energy & Atmosphere

Sustainable Sites

Water Efficiency

Energy & Atmosphere

Materials & Resources

Indoor Environmental Quality

Innovation & Design Process

Credit 1: Optimize Energy Performance (Replaces LEED-NC Credit 1)

Intent

Achieve increasing levels of energy performance above the baseline in the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use.

Requirement

Demonstrate a percentage improvement in the proposed building performance rating compared to the baseline building performance rating per ASHRAE/IESNA Standard 90.1-2007 by a whole building project simulation using the Building Performance Rating Method in Appendix G of the Standard as well as the requirements of the Labs21 Laboratory Modeling Guideline. The minimum energy cost savings percentage for each point threshold is as follows:

New Buildings Existing Building Renovations Points
12% 8% 1
16% 12% 2
20% 16% 3
24% 20% 4
28% 24% 5
32% 28% 6
36% 32% 7
40% 36% 8
44% 40% 9
48% 44% 10

Appendix G of Standard 90.1-2007 requires that the energy analysis done for the Building Performance Rating Method include ALL of the energy costs within and associated with the building project. To achieve points using this credit, the proposed design—

  • must comply with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in Standard 90.1-2007;
  • must include all the energy costs within and associated with the building project; and
  • must be compared against a baseline building that complies with Appendix G to Standard 90.1-2007 as well as the requirements of the Labs21 Laboratory Modeling Guidelines. The default process energy cost is 25% of the total energy cost for the baseline building. For buildings where the process energy cost is less than 25% of the baseline building energy cost, the LEED submittal must include supporting documentation substantiating that process energy inputs are appropriate.

For the purpose of this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators, kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g. lighting integral to medical equipment) and other (e.g. waterfall pumps). Regulated (non-process) energy includes lighting (such as for the interior, parking garage, surface parking, fašade, or building grounds, except as noted above), HVAC (such as for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, laboratory fume hoods etc.), and service water heating for domestic or space heating purposes.

For EA Credit 1, process loads shall be identical for both the baseline building performance rating and for the proposed building performance rating. However, project teams may follow the Exceptional Calculation Method (ASHRAE 90.1-2007 G2.5) to document measures that reduce process loads. Documentation of process load energy savings shall include a list of the assumptions made for both the base and proposed design, and theoretical or empirical information supporting these assumptions.

Technologies & Strategies

Design building systems to maximize energy performance while maintaining or improving health and safety requirements. Consider the following strategies in particular:

  • Use high performance low-flow fume hoods.
  • Use variable air volume fume hoods (combined with VAV supply and exhaust) assuming maximum 50 percent flow turndown between design maximum and minimum volume.
  • Use energy (latent and sensible) recovery.
  • Eliminate simultaneous heating and cooling.
  • Use evaporative cooling when ambient conditions allow.
  • Minimize outside air to 1 cubic foot per minute per square foot (cfm/sf) or less.
  • Reduce unoccupied outside airflow during unoccupied periods.
  • Expand unoccupied temperature dead band by automatically resetting zone temperature set points based on occupancy.
  • Encourage small HVAC zones with no 100 percent outside air control zones greater than 1000 square feet.
  • Provide a cooling system with at least two cooling loops operated at different temperatures. This can be accomplished with separate chillers (or direct tower cooling).
  • Design for high part-load heating and cooling efficiency.

Use a computer simulation model to assess the energy performance and identify the most cost effective energy efficiency measures. Quantify energy performance as compared to a baseline building.

The Labs21 Laboratory Modeling Guideline is available at: http://www.labs21century.gov/toolkit/bp_guide.htm

 

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