Minimum energy performance | U.S. Green Building Council
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| v3 - LEED 2009

Minimum energy performance

EAp2 | Required


To establish the minimum level of energy efficiency for the proposed building and systems to reduce environmental and economic impacts associated with excessive energy use.


Option 1. Whole building energy simulation

Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building performance rating.

Calculate the baseline building performance rating according to the building performance rating method in Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) using a computer simulation model for the whole building project. Projects outside the U.S. may use a USGBC approved equivalent standard2.

Appendix G of Standard 90.1-2007 requires that the energy analysis done for the building performance rating method include all energy costs associated with the building project. To achieve points using this credit, the proposed design must meet the following criteria:

  • Comply with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in Standard 90.1-2007 (with errata but without addenda1) or USGBC approved equivalent.
  • Inclusion of all the energy costs within and associated with the building project.
  • Compare against a baseline building that complies with Appendix G of Standard 90.1-2007 (with errata but without addenda1) or USGBC approved equivalent. The default process energy cost is 25% of the total energy cost for the baseline building. If the building’s process energy cost is less than 25% of the baseline building energy cost, the LEED submittal must include documentation substantiating that process energy inputs are appropriate.
  • Obtain an energy performance rating for estimated energy use of both the baseline and proposed design from EPA’s ENERGY STAR Target Finder design tool and submit the Statement of Energy Design Intent document, generated by Target Finder, as part of the project’s design submittal.

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 (for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilation and air conditioning (HVAC) (for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes.

Process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard 90.1-2007 G2.5) or USGBC approved equivalent to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and the proposed design, and theoretical or empirical information supporting these assumptions.

Projects in California may use Title 24-2005, Part 6 in place of ANSI/ASHRAE/IESNA Standard 90.1-2007 for Option 1.


Option 2. Prescriptive compliance path: ASHRAE Advanced Energy Design Guide (AEDG) for Small Hospitals and Healthcare Facilities.

Comply with the prescriptive measures of the ASHRAE Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities. The following restrictions apply:

  • Buildings must be 90,000 square feet (8,360 square meters) or less.
  • Project teams must fully comply with all applicable criteria as established in the AEDG for the climate zone in which the building is located. Projects outside the U.S. may use ANSI/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.


Option 3. Prescriptive compliance path: prescriptive path for energy improvements in hospitals
  • Buildings must be over 90,000 square feet (8,360 square meters).
  1. Comply with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in ASHRAE Standard 90.1-2007
  2. Incorporate all Energy Efficiency Measures (EEMs) listed below:
    • High Performance Windows and Glazing
    • Thermally broken metal window frames
    • U value at the center of glass < 0.29
    • Solar heat gain coefficient at the center of glass < 0.38
    • U value of the window including framing effects < 0.40
  3. Lighting Power Density (LPD)
    • Reduce interior LPD a minimum of 10% below IESNA/ASHRAE Standard 90.1 –2007.
    • Reduce exterior lighting power density to 20% below IESNA/ASHRAE 90.1-2007 requirements.
  4. Lighting Controls
    • Install occupancy sensor lighting controls, at a minimum, in all offices, storage areas and mechanical spaces to achieve the following lighting energy reduction:
      • Offices: 15% during the day
      • Storage: 60% during the day; 30% at night
      • Mechanical Spaces: 50% for 23 hours/day
  5. The HVAC system serving all areas shall include Variable Air Volume (VAV) air handling units supplied by a central chilled water and boiler plant. In addition, provide zoning controls to maintain pressure relationships as specified in the 2010 FGI Guidelines for Design and Construction of Health Care Facilities. Zoning controls shall be used on both supply air and return/exhaust air systems.
  6. Reduce fan power a minimum of 10% less than the limit under ASHRAE 90.1-2007.
  7. Reduce turndown ratio on VAV boxes in accordance with ASHRAE 90.1-2007 Prescriptive Requirement
  8. Design the heating plant, including boilers and auxiliary equipment, to achieve a minimum systemefficiency (BTUH output/ BTUH input) of 90%
  9. Design hot and chilled water pumps (3 hp [2.24 kW] or greater) with variable speed drives and a minimum part load ratio of 30%.
  10. For fans and pumps, use only motors that meet National Electrical Manufacturers’ Association (NEMA) standards for premium efficiency.
  11. Chillers shall operate at a maximum of 0.52 kW/ton (0.15 kW/kW) at full load and an Integrated Part Load Value (IPLV) of 0.399 kW/ton (0.11 kW/kW).

Pilot ACPs Available

The following pilot alternative compliance path is available for this prerequisite. See the pilot credit library for more information.

EApc95: Alternative Energy Performance Metric ACP

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