CI-2009 EAc1.3: Optimize Energy Performance—HVAC

  • CI_EAc1-3_Type1_HVAC Diagram
  • What’s in your scope

    This credit requires that you demonstrate energy savings from HVAC systems and components within your project scope—only systems installed as part of the LEED-CI project, or systems within the LEED boundary. (See more detail on scope below.)

    Two options, for up to ten points

    There are two options for achieving this credit, either of which could earn five or ten points for your project. 

    • Option 1 uses a prescriptive approach. You earn five points for calculating building loads and meeting mechanical system efficiency requirements in accordance with the Advanced Buildings: Core Performance Guide (CPG), Sections 1.4, 2.9, and 3.10. You can also, separately or in addition, earn five points by demonstrating appropriate zoning and controls to promote energy efficiency. 
    • Option 2 is a performance approach for projects that use energy modeling to predict how much energy they’ll save. Your project has to show 15% savings (compared to the minimum performance guidelines of ASHRAE 90.1-2007) to earn five points, or a 30% savings for an additional five points. These are challenging thresholds, because you can only count savings from HVAC systems and equipment and you have to reach one of these thresholds to earn any of the points—prorating is not an option. An Exemplary PerformanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. point via IDc1 is also available if you can demonstrate 33% energy savings. 

    Which way to go?

    If your HVAC equipment is fairly conventional, it will likely be listed in the CPG, making Option 1 the easiest approach for five points. More unique or innovative systems may find it better to go with energy modeling.

    Is your project located in a LEED-certified building? If so, investigate if the building already has an energy model that you could adapt for this credit, potentially saving cost and enabling you to earn a better score. If not, consider whether your project scope is large or complex enough to warrant using an energy model.

    Watch out for hidden requirements

    To achieve the first five points in Option 1 the design engineer has to demonstrate that the HVAC system in the space can maintain minimum temperature and humidity ranges that meet ASHRAE-55. This requirement makes those points tricky for projects that do not have humidity control, especially in regions with high humidity. These points also require that you have a mechanical system with efficiency requirements listed in the CPG included in your project. For example, a project with VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. boxes only will not be eligible for the credit, but a project with a split system will. 

    Option 2 is challenging because for a small CI project the cost of creating an energy model might outweighs the benefit of the potential energy savings achieved from using the model as a design tool. If the base-building has already developed a model, this is often more cost-effective. 

    It’s the scope that matters

    A typical HVAC installation in an office fit-out has a minimal scope. Often the base building’s mechanical systems supply the space with heating and cooling and ventilation air. What is left to the fit-out team is the distribution system which includes diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light., VAV boxes, and controls. In LEED Interpretation #10134, issued on 11/1/11, USGBC clarified the level of HVAC equipment that must be installed to make a LEED-CI or LEED-Retail-CI project eligible for EAc1.3, Option 1, as being one of the following:

    • Air handlers with Variable Speed Controls complying with the requirements of the Core Performance Guide Section 3.10 that supply at least 60% of the total supply air volume used within the project scope.
    • Mechanical equipment that complies with the prescriptive efficiency requirements of the Core Performance Guide Section 2.9, and provides at least 60% of the cooling or heating capacity for the project scope.
    • The project can comply with the requirements of the credit if the project team can show that the relevant criteria have been met for all HVAC systems serving the area within the project scope, whether or not the HVAC systems are installed as part of the tenant scope of work.

    Another LEED Interpretation, #10135, further clarifies project scope for this credit, noting that "'project scope' refers to all spaces within the LEED project boundary, regardless of whether or not they are included in the project's scope of work. The project can comply with the requirements of the credit as long as all spaces within the 'project scope' satisfy the requirements."

    This Interpretation also notes, "Each private office must have its own active controls. Grouping of offices using a single control does not meet the intent of the requirements."

    FAQs for EAc1.3

    If pursuing Option 2, what is the scope of the energy model if the space shares a central plant, and what type of software should be used?

    If your space shares a central HVAC plant you need to model the whole building. Consider using energy modeling software, like eQuest, that can separately account for the energy use of the base building separately from your project space by adding additional electricity and gas meters for each space within the model. This is easier and more accurate to model and more likely to be accepted by GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). reviewers.

    For Option 1, Zoning and Controls, is a thermostat considered an “active control capable of sensing space demand"?

    Thermostats alone do not meet this definition. LEED Interpretation 10242, issued 10/1/12, clarifies what is expected:

    • "Active control is the control capable of sensing space occupancy and adjusting the HVAC system demand based on the changes in space occupancy, which does not equal a thermostat or a separate thermal zone for each space."
    • "For VAV systems and non-VAV systems, active controls typically regulate the required outdoor air flow for ventilation, such as using demand controlled ventilation with CO2Carbon dioxide sensors in each private office and specialty occupancy space, or regulate temperature set point based on occupancy by adjusting the HVAC system to operate under the unoccupied set back when occupant sensors indicate that the space is unoccupied."
    • "Alternatively, VAV systems meeting all the requirements in LEED Interpretation 5273 are also eligible. However, those systems which do not modulate the system level supply air flow but only redirect the excess air back to the ceiling void or return air duct under low demand conditions are not eligible for this alternative compliance path."
    • "For a VRF system or another constant volume system with separate thermal zones for each specialty occupancy or private office, the following active controls would be considered sufficient to meet the credit criteria". (See Interpretation 10242 for the full guidance.)

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • Both Options


  • The designer and mechanical engineer review the referenced sections of the Core Performance Guide (CPG). 


  • Decide which option best suits your project. Either way, you can only achieve 5 or 10 points, and nothing in between.

    • Under Option 1 you can earn points for using efficient equipment (5 points) and/or zoning and controls (5 points).
    • Under Option 2 you have to show energy savings using a computer-based energy model demonstrating a 15% cost savings from the ASHRAE 90.1-2007 baseline building for 5 points or a 30% savings for 10 points. 

  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls 


  • Review sections 1.4, 2.9, and 3.10 in the Advanced Buildings: Core Performance Guide (CPG) to understand the requirements and how they relate to the systems to be installed in the project:

    • Section 1.4: Mechanical System Design – Perform project-specific load calculations during design to properly size mechanical equipment and to ensure efficiency and comfort by meeting ASHRAE-55 requirements for temperature and humidity.
    • Section 2.9: Mechanical Equipment Efficiency requirements – Meet or exceed the minimum requirements for efficiency for listed equipment in the CPG.
    • Section 3.10: Variable Speed Control – Provide variable flow capabilities for air and fluid systems by specifying variable speed fans and pumps with a motor horsepower of 5 hp or greater. 

  • You can only count HVAC components that are within the CI scope of work.


  • To achieve the first five points in Option 1 the design engineer has to demonstrate that the HVAC system in the space can maintain minimum temperature and humidity ranges that meet ASHRAE-55. This requirement makes those points tricky for projects that do not have humidity control, especially in regions with high humidity.


  • Review the zoning and controls requirements to see what it will take to achieve these five points (you have to meet all three requirements to earn any points):

    1. Each solar exposure (interior space with an exterior wall) has to have a separate control zone.
    2. All interior spaces separated by full, floor-to-ceiling partitions have to be separately zoned.  
    3. Private offices and other spaces with special occupancies must have active controls that can sense occupancy and modulate the HVAC system in response to demand, such as a CO2 monitor or occupancy sensor.

  • Note: If the base building HVAC system can’t be modulated in response to space demand, as with many VAV systems where one zone cannot be the control point of the entire air-handler’s outside air damper minimum position, the design has to meet the following criteria.

    1. The system has to be capable of modulating air-handling units (AHUs) and zone minimum supply volume below 0.30 cubic feet per minute per square foot of supply volume for standard VAV terminals, or below 22.5% of the peak design flow rate for fan-powered VAV boxes. For spaces where the minimum outdoor air flow exceeds the minimum supply volumes specified here, use occupant sensors or DCV to achieve these minimum supply volumes.
    2. The building control system has to include controls for fan static pressure reset.
    3. The mandatory requirements of ASHRAE 90.1-2007 and ASHRAE 62.1-2007 have to be met.

  • A “zone” implies an area with independent control of mechanical HVAC that typically includes its own thermostat and sensors to control air flow or temperature in a space. 


  • Identify each solar exposure and the spaces that correspond to those exposures that have to have a separate control zone. An “exposure” is an external wall that’s included in your project scope. Identify all the external walls in your floor plan, and indicate which direction each faces: north, south, east, or west.


  • Identify all interior spaces (those without an exterior wall) to be separately zoned. 


  • Identify all private offices and spaces with specialty uses—such as break rooms and conference rooms—to understand how many active controls you’ll need.  


  • Small (<200 ft2) private spaces intended for temporary occupancy like janitor closets, and mechanical rooms can be included as part of a larger zone. 


  • It’s a good idea at this stage to have your mechanical engineer meet with the base building engineer or manager to get detailed information on the possibility of adding controls and outside air intake—and to explore the possibilities of improving the efficiency of the system as a whole. The base building manager can also benefit from becoming familiar with the tenant’s design, which might lead to greater control and system integration.


  • Option 2: Energy Cost Reduction – 15%–30% 


  • Find out if it’s feasible to pursue this option. You’ll need to have (or be able to generate) a computer-based energy model running on approved software.


  • Option 2 is best for projects with unique mechanical systems and energy efficiency strategies that are not included in Advanced Buildings: Core Performance Guide, thus not fitting well with Option 1. 


  • If your project has a larger HVAC scope, one that includes boilers, chillers, or air handling units, it may make sense to develop an energy model to assist in system sizing and selection.


  • If energy modeling has already been initiated by the base building project team, this is the way to go. If your project is located in a LEED-certified building, it’s likely that an energy model has already been done. If so, check with your building’s owner about accessing the energy model files and results. 


  • It is not easy to achieve 15% or better energy cost savings over current energy codes, such as ASHRAE 90.1-2007, from space heating, cooling, fans, and pumps alone, even though you can factor in HVAC load reductions from envelope improvements and lighting in the equipment energy use calculation.


  • Developing a simulation model isn’t cheap—in the range of $10,000–$30,000 depending on the complexity of the project—but modeling can provide a favorable payback through design optimization and energy savings. 


  • Many CI projects with limited HVAC design scope find it more cost-effective to pursue Option 1. The usefulness of energy modeling as a design and optimization tool depends upon how wide the project scope is—the more systems that can be influenced in the design process, the better.


  • The energy modeler should be contracted during early design phase to provide recommendations for a high-performing system and equipment selection along with ideas about potential energy savings, cost estimates, and payback periods.  


  • Pursuing the energy model option can help you document compliance with the energy prerequisite. It can also be useful in applying for financial incentives, which are usually based on a percentage reduction (energy saved) relative to your local code.

Schematic Design

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  • Both Options


  • Include key HVAC efficiency targets in the Owners Project Requirements (OPR) document for commissioning (see EAp1 and EAc2), with input from the mechanical engineer and other design team members. Use metrics such as number of points to be achieved, HVAC efficiency levels, or HVAC percentage improvement over a baseline. Having those targets in the OPR will help the team develop a design strategy to meet goals for energy efficiency.


  • Strategize a design direction to meet these goals. Identify ways to reduce energy use by involving the mechanical engineer, architect, lighting designer, owner, and landlord in system design discussions. If applicable, explore passive design techniques within the scope of the interior fit-out. 


  • Encourage an integrated design that includes input from the design team and owners, as well as the architect, lighting designer, mechanical engineer, and others - to align space utilization, window treatments, lighting layout, and thermal zoning to create the most effective design.


  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls 


  • Review the Core Performance Guide (CPG) for guidance on load calculations, mechanical equipment selection, and zoning and control requirements. The CPG is a manual that has a format similar to ASHRAE guidelines, so it is best interpreted by a design engineer.


  • Pay attention to these key points about implementing the requirements of CPG Section 1.4: Mechanical System Design:

    • Following ASHRAE-55 requires part-load and full-load calculations to ensure optimal efficiency while keeping occupants comfortable throughout the year.
    • For heating and cooling equipment, you need to perform load calculations with assumptions that are consistent with the CPG, including accurate characterization of lighting, solar gain, glazing performance, occupancy, and ventilation loads based on the specific design characteristics of the project. 
    • For ventilation equipment, you need to document fan-sizing calculations with zone-by-zone load calculations. 
    • To perform part-load calculations, use benchmark data, average daytime temperatures, non-peak solar gain, and other assumptions to define part-load conditions for the heating and cooling system. 

  • Describe the features of your design that can facilitate efficient operation at part-load conditions, and document how your system plans to maintain adequate ventilation air and comfort as required by ASHRAE-55. 


  • If your project is also pursuing IEQc 7.1: Thermal Comfort—Design, the procedures and documentation for that credit will also work for following CPG Section 1.4.


  • Following Section 2.9: Mechanical Equipment Efficiency, specify all systems within your project scope at performance efficiency equal to or higher than the minimum efficiencies listed in CPG Tables 2.9.1–2.9.6. 


  • Following Section 3.10: Variable Speed Control, specify variable speed drives on pumps and fans greater than 5 hp. 


  • In typical air-conditioned spaces, 20%–30% of energy used is for delivering the conditioned air to the space through ducts and fans. The volume of air depends on the load requirement, which varies with occupancy, latent heat load, and outside weather. Because of variations within all these parameters, delivered air volume should be modulated in occupied spaces with CO2 monitors, VAV boxes, or both to save energy.


  • The majority of space uses can benefit from variable air volume (VAV) distribution. Some projects, like warehouses and data centers, may not include variable load parameters and so would not save energy with VAVs. In those cases, you can provide a supporting narrative arguing against installing VAV. These less typical projects might benefit from following Option 2. 


  • Review zoning and controls compliance. Make sure that under the proposed mechanical design each interior space with a different exposure is a separate control zone, all appropriate interior spaces have been zoned separately, and that the required demand responsive controls are included.


  • If they haven’t done so already, have your design engineer develop a cost estimate for the additional zoning and controls required to meet the requirements. Consider whether the benefits in terms of energy savings and improved indoor air quality of the additional controls are worth the cost of installation.


  • Consider space programming in collaboration with mechanical system zoning. You may want to link similar functions together for mechanical zoning reasons. A floor with an open-plan office space that will only be occupied in the daytime can be controlled by one zone that allows for a reasonable degree of efficiency. On the other hand, if that open-plan office floor also has enclosed conference rooms and private offices, a single zone won’t allow users to adjust temperature and airflow to the enclosed rooms when they are unoccupied, so energy will be wasted.


  • If your project is installing a Building Management System (BMS), consider scheduling or occupancy sensors that reduce air flow and setback the air-conditioning temperature in unoccupied spaces. 


  • Option 2: Energy Cost Reduction – 15%–30% 


  • Engage an energy modeler to review the preliminary designs and make recommendations on programming and integration with existing systems. If you still have any options relating to orientation and shading, look at those as well.  


  • Give your energy modeler all relevant, energy-related information on the project, including glazing specifications, wall insulation, roof specifications, building uses on other floors, approximate lighting power use, site plan, and the operating schedule of base-building mechanical systems. Collecting this information will involve the owner, who can connect the energy modeler with the base-building engineer. You can use past energy bills to approximate the energy performance that needs to be input by the energy modeler.


  • Determine the energy model’s scope. In general, to simulate the performance of building systems an energy model has to include all spaces served by a common HVAC system. However, central HVAC systems often extend beyond the scope of CI projects. For example, if the project scope is a single floor fit-out in a four story building, it’s likely that the building HVAC systems will serve all four floors. The model will simulate the energy use of all four floors, but the CI project can account for only a portion (25% in this case) of the energy use and energy savings from efficiency upgrades.


  • Start the energy modeling by building the design-case model. Follow Section 11 (Energy Cost Budget) or Appendix G (Performance Rating Method) of ASHRAE 90.1-2007 guidelines for assistance with modeling parameters. Input the existing building’s envelope characteristics, but use project design specifications for energy-using equipment and systems. 


  • Using the Energy Cost Budget method may be more cost effective for your project, as it’s less comprehensive and detailed. However, it does not include savings for energy efficient air distribution systems. If this is where your project is expected to realize significant energy savings, use the Performance Rating Method.  


  • If your project is in a LEED-certified building, a model using the performance rating method may already exist and can be modified to document this credit. 


  • Modifications to the building HVAC system that are to be implemented concurrently with your project should also be included. (These modifications need not be within your project scope.) 


  • Create the baseline model. Two baseline model calculation methods are available; explore both to determine which one is better for your project:

    • Existing Conditions Baseline. This model includes the existing conditions of the building, but all systems must comply with the minimum ASHRAE 90.1-2007 efficiency guidelines. This calculation method is more beneficial for projects located in less-efficient buildings. Savings calculations for this model are adjusted to include only the area within the project scope or building segment.  
    • Alternative Baseline. This is intended for projects located in energy-efficient or LEED-certified buildings. For buildings that exceed the efficiency guidelines of ASHRAE 90.1-2007, the baseline can be adjusted down to the meet these guidelines. In addition, the calculations include the overall savings of the modeled HVAC system and are not adjusted relative to the project area or building segment. These adjustments are allowed so the project isn’t penalized for being in an efficient, possibly LEED-certified, building.  

  • The operational performance of the base building affects the performance of the tenant space. Sometimes the current operator doesn’t know the specifications of the base-building systems that are being modeled, so request as much information as you can, including operations and maintenance manuals that might provide more details. 


  • If pursuing Option 2, and you need to model the whole building because your space shares a central HVAC plant, consider using energy modeling software, like eQuest, that can account for energy use of the base building separately from your project space.  This is more likely to be accepted by the reviewers.

Design Development

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  • All Options


  • Reduced energy loads can translate into lower construction costs because you might be able to get by with smaller equipment; including fans, pumps and auxiliary systems; and less ductwork. 


  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls 


  • Review the following sections of the Core Performance Guide (CPG) and credit requirements:

    • Section 1. 4 – Check that the part-load calculations have been completed and that compliance with ASHRAE-55 has been confirmed.
    • Section 2.9 – Ensure that your project’s mechanical design and equipment comply with the CPG efficiency requirements.
    • Section 3.10 – Verify that the highest efficiency fans and pumps have been identified. Variable frequency drive pumps and variable air volume (VAV) distribution systems can be used to address fluctuating demand. Sensors and controls to measure air volumes and reduce energy waste during low occupancy should be installed. 
    • Appropriate Zoning and Controls – Further develop designs for the separate zones and controls to be installed. Confirm that these meet the requirements. 

  • Option 2: Energy Cost Reduction – 15%–30% 


  • Early in design development, engage the energy modeler in reviewing the recommendations for reaching the 15% and 30% energy reduction thresholds. See the LEED-NC energy modeling guidelines for an overview of the energy modeling process and specific guidance on creating the energy model. 

Construction Documents

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  • All Options


  • Call out the efficiency ratings of selected equipment on mechanical equipment schedules to make sure that the proper model is selected and that the system is installed according to design intent.


  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls


  • Ensure that your project is in compliance with all the prescriptive requirements outlined in the Advanced Buildings: Core Performance Guide, Sections 1.4, 2.9, and 3.10. Complete the prescriptive checklist, and collect equipment cut sheets.  


  • This is an all-or-nothing option: If even one requirement is not met, all five points are lost.


  • Develop drawings and specifications for the zones and controls.


  • Option 2: Energy Cost Reduction – 15%–30% 


  • Ensure that specified HVAC systems and components match or exceed the efficiency requirements of the systems in the final, accepted energy model. Also, ensure that these systems, with their corresponding performance ratings, are included in the appropriate schedules and plans.

Construction

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  • Confirm the installation of the selected equipment. 


  • Document the credit requirements on LEED Online, per the option you selected.


  • For Option 1: Equipment Efficiency & Appropriate Zoning and Controls, document the following:

    • Section 1.4 - Upload a summary of load calculations for heating, cooling and fan sizing, including assumptions and results at full load and part load.
    • Section 2.9 – Have your mechanical engineer sign off on the template that the efficiency requirements have been met. 
    • Section 3.10 – Fill out the template with the variable speed fans and pumps included in the project, their location, and design wattage demand at 50% of design flow. 
    • Appropriate Zoning – Indicate that all requirements for zoning have been met on the template. Also, include a narrative that describes the building-level HVAC system as well as that serving the tenant space, how the zones were determined, the control logic, as well as anticipated energy savings. 

Operations & Maintenance

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  • Monitor equipment energy use over time to confirm that the projected savings are achieved.  


  • Engage a commissioning authority as part of EAc2: Enhanced Commissioning.

  • USGBC

    Excerpted from LEED 2009 for Commercial Interiors

    EA Credit 1.3: Optimize energy performance - HVAC

    5-10 Points

    Intent

    To achieve increasing levels of energy conservation beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use.

    Requirements

    MANDATORY POINT MINIMUM: Project registered on or after April 8, 2016 must earn four points in this credit, but can come from any of the four sub-sections.
    Option 1

    Implement 1 or both of the following strategies:

    • Equipment Efficiency—(5 points)

      Install heating, ventilation and air conditioning (HVAC) systems that comply with the efficiency requirements outlined in the New Building Institute’s Advanced Buildings™ Core Performance™ Guide Sections 1.4: Mechanical System Design, 2.9: Mechanical Equipment Efficiency and 3.10: Variable Speed Control.
    • Appropriate Zoning and Controls: (5 points)

      Zone tenant fit out of spaces to meet the following requirements:
      • Every solar exposure must have a separate control zone.
      • Interior spaces must be separately zoned.
      • Private offices and special occupancies (conference rooms, kitchens, etc.) must have active controls capable of sensing space use and modulating the HVAC system in response to space demand.

    OR

    Option 2

    Reduce design energy cost compared with the energy cost budget for regulated energy components described in the requirements of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1). Projects outside the U.S. may use a USGBC approved equivalent standard2.

    AND

    Path 1 (5 points)

    Demonstrate that HVAC system component performance criteria used for tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. are 15% better than a system in minimum compliance with ANSI/ASHRAE/IESNA Standard 90.1–2007 (with errata but without addenda1) or USGBC approved equivalent.

    OR

    Path 2 (10 points)

    Demonstrate that HVAC system component performance criteria used for tenant space are 30% better than a system that is in minimum compliance with ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) or USGBC approved equivalent.

    Potential Technologies & Strategies

    Design the HVAC system components to maximize energy performance. Review compliance options for EA Credit 1.3 and determine the most appropriate approach. Option 1 provides a more prescriptive approach to recognizing energy-efficient HVAC design, while Option 2 is performance based.

    FOOTNOTES

    1. Project teams wishing to use ASHRAE approved addenda for the purposes of this credit may do so at their discretion. Addenda must be applied
    consistently across all LEED credits.

Web Tools

Energy Analysis Tools

This website discusses the step-by-step process for energy modeling.

Technical Guides

Advanced Buildings Core Performance Guide

A guide for achieving energy efficiency in new commercial buildings, referenced in the LEED energy credits.


ASHRAE 2007 HVAC Compliance Forms

Key forms for this credit include the following: Standard 90.1-2007: HVAC Compliance Documentation (PDF), part 1; Standard 90.1-2007: HVAC Compliance Documentation (PDF), part 2; Standard 90.1-2007: HVAC Compliance Documentation (PDF), part 3; Standard 90.1-2007: HVAC Compliance Instructions (PDF).

Software Tools

Building Energy Software Tools Directory

DOE tools for whole building analyses, including energy simulation, load calculation, renewable energy, retrofit analysis and green buildings tools.

HVAC Design Narrative

Option 1

This example narrative of HVAC system serving the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. and the building level system describes how the zones and controls were determined, and anticipated energy savings.

HVAC Construction Documents

Options 1 and 2

The full HVAC system plans and specifications shown in this example demonstrate compliance with credit requirements.

HVAC Load Calculations

Option 1

These examples of summary load calculations for the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. show assumptions and results at full- and part-load, and compliance with ASHRAE-55.

CI-2009 LEED Online Sample Forms – EA

The following links take you to the public, informational versions of the dynamic LEED Online forms for each CI-2009 EA credit. You'll need to fill out the live versions of these forms on LEED
Online
for each credit you hope to earn.

Version 4 forms (newest):

Version 3 forms:

These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions for these forms; for more information, visit LEED Online and click "Sample Forms Download."

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

449 Comments

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Jayakumar Pamuri
Oct 25 2016
Guest
4 Thumbs Up

Chilled water flow and pipe sizes

Project Location: Oman

Hi All, I am here to post my query about chilled water system,flow and pipe sizes.

As everybody know chilled water flow is 1.5 usgpm/tr when chiller is selected at delt T 16°F & 2.4 usgpm/tr when chiller is selected at delt T 10°F.
But, what will be the problems if Chiller is selected/designed to produce delt T of 16°F and the chilled water flow rate & pipe size is designed at 2.4 usgpm/tr.

Thanks......

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Bazeeth Ahamed K M Conserve Green Building and MEP Solutions WLL Oct 26 2016 LEEDuser Member 89 Thumbs Up

Hi
You have selected the pipe for 2.4 gpm/TR where as the actual flowrate is 1.5 gpm/TR. So the velocity in the pipe will be lesser.Which means that you have over sized your pipes. It is a good idea to resize the pipe for actual flowrate to reduce the piping cost. If you prefer to keep the existing pipe sizes, You have ensure that the velocity is within in recommended limit.

Post a Reply
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Yuna Chen
Sep 28 2016
LEEDuser Member
24 Thumbs Up

appropriate zoning, solar exposure - apartment

Hi,

My project is a student dorm building with some faculty apartments. The faculty apartment might have two or three bedrooms and one living rooms, etc. The bedrooms and living rooms are facing different orientations.

For this EAc1.3 appropriate zoning "every solar exposure has a separate control zone" requirement, do i need to have different controls in this case? For example, if bedroom 1 and bedroom 2 are facing S and E, do i need to provide two thermostat/fan coils, one in each bedroom?

I am hoping an apartment can be treated as one zone for this credit so that we only need to have one control in each apartment?

Appreciate your input.

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Marcus Sheffer LEED Fellow, 7group Oct 06 2016 LEEDuser Expert 65859 Thumbs Up

Obviously the requirements were written for an office building. Check the interpretations to see if there is anything about how to apply this to a residential project. If not you may need to submit your own inquiry or interpretation.

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0
MKK LEED
Sep 22 2016
LEEDuser Member
190 Thumbs Up

ECB vs Appendix G

Project Location: United States

I am trying to understand whether the modelling for Option 2 of this credit is supposed to be done using the ECB method or Appendix G. In the initial option wording it says ECB, but under the paths it says 90.1 not specifying a section. One project I am considering currently this would make a big difference to, since ECB would have my water source HP system in the baseline as well, where AppG would have a VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system as the baseline. I have previously been told, though I can't now find the reference, that ECB isn't supposed to be used to show percent improvement, only for compliance purposes, so AppG was my instinct. Step 6 of the method talks about Section 11 or Appendix G, do I get to choose? If anyone has done this before I'd appreciate comments, in previous CI projects I have only seen Option 1 being used.

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Marcus Sheffer LEED Fellow, 7group Sep 23 2016 LEEDuser Expert 65859 Thumbs Up

You get to choose.

The full procedure for doing this modeling is contained in the Reference Guide.

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SAMY Chamy Enginneer T&T Green
Sep 07 2016
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TFA (Treated Frtesh air unit) - Energy Modeling

Dear all:-

Our project have installed with VRF with TFA Unit

Due to TFA unit usage we have significant saving in HVAC because outdoor air supply temperature is very low now we have some doubts in this TFA unit at Energy modeling

Note :- This TFA unit is not interlocked with HVAC system (VRF) & the Fresh air and Dehumidified air ratio is below 30% only

Doubts are

1.How we model these TFA unit Either Identically or for proposed case only
2.Can we take a advantage of TFA unit in proposed case alone or Both cases (can we take fresh air supply temperature as same as ambient outdoor dry bulb temperature in Baseline case)
3.Additionally TFA unit is located in Rooftop only can we exclude the energy cost of those TFA unit in HVAC cost because these kind of Loads are considered as process load and modeled Identically in LEED NC.

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SAMY Chamy Enginneer, T&T Green Sep 12 2016 Guest 616 Thumbs Up

Dear All:-

Awaiting for your reply

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Marcus Sheffer LEED Fellow, 7group Sep 12 2016 LEEDuser Expert 65859 Thumbs Up

1. Sounds like a dedicated outside air system. This only gets modeled in the proposed and not in the baseline.

2. Yes you can.

3. No. The proposed must be modeled as designed.

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SAMY Chamy Enginneer T&T Green
Aug 24 2016
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616 Thumbs Up

LEED CI - HVAC Syatem selection and Fan power Modeling

Dear All:-

How to select the Baseline HVAC system for LEED CI Project and how I calculate the fan power for fan interlocked with HVAC system

Can we us the 7Group fan power calculator for baseline HVAC fans

Actual building HVAC system is VRF and our project area is 20000 Sq.ft office only so which is our baseline system

In which basis base case system is selected at ASHRAE 11.3.2 either by Air conditioned area of project or others

if we model VRF as baseline HVAC means how can we have saving in HVAC system

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Marcus Sheffer LEED Fellow, 7group Aug 24 2016 LEEDuser Expert 65859 Thumbs Up

Yes you can use the fan power calculator if using Appendix G.It appears to be the same in Section 11 but I am not certain of that.

For a Section 11 model I think you are a System #9 but I have not applied that section in a very long time. See Figure 11.3.2.

For Appendix G you are a system 4.

There are no VRF baselines.

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SAMY Chamy Enginneer T&T Green
Aug 18 2016
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LEED CI - Energy Modeling Terms

Dear All:-

Greetings

I need some clarity in terms in the terms used in "LEED ID + C ref guide page no 172"

what is meant by
1.Project area
2.Total Segment area of LEED CI project ECB energy simulation

The Issues are

1.Can we include the Entire building in energy modeling or just LEED CI floor area

2.my project building is existing building and we just change the interior lights and bulbs for out interior space only so can we take my previous lighting, envelope and HVAC as my BASE case or ASHRAE as my basecase

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Marcus Sheffer LEED Fellow, 7group Aug 19 2016 LEEDuser Expert 65859 Thumbs Up

1. The area of the CI project.
2. The portion of the building included in your model. This could be part of the building or the whole building. See Step 2 on page 169.

1. Usually you will need to model more than just the CI area but it depends on the HVAC system configuration.

2. For building envelop you can use the previous (Table G3.1-5 Baseline (f)). For lighting and HVAC you use ASHRAE baseline.

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SAMY Chamy Enginneer T&T Green
Aug 13 2016
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616 Thumbs Up

Energy Modeling

Dear All:-

How to do energy modeling for LEED CI

In LEED CI the energy saving is compared for Space heating and Cooling only,

1.Am I Correct
2.Can we consider different Building envelope for Both cases ( Base case - ASHRAE Construction Envelope depend upon Climatic zone and actual Building envelope for design case
3.Can we consider different Interior Lighting power for Both cases ( Base case - ASHRAE allowable LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. based on space or building type and actual Lighting power for design case
4.We have very efficient 5 star rated Computers and scanners so can we take a conventional 3 star rated computers and scanners for base case because all other Commercial stores are used 3 star rated products only due to that we have quantified energy saving in space cooling compared to other stores

Because we have best Construction envelope and efficient lighting & Equipment's (PC & Scanners) so can we take these advantage in space heating and cooling

Please advice how to model the Lighting, Equipment and construction envelope

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Marcus Sheffer LEED Fellow, 7group Aug 16 2016 LEEDuser Expert 65859 Thumbs Up

The cost savings for this credit are determined for heating and cooling only. You do model all energy use and there can be differences in the models for energy end uses other than HVAC. Some of those end uses will influence the HVAC energy use but their savings do not count toward credit achievement directly. You basically create the two models as usual and then just compare the HVAC cost savings to determine credit achievement.

The specific method to use when creating the models is fully explained in the Reference guide.

There is an alternate modeling method outlined in LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 10412 that replaces EAc1.1 to 1.4.

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SAMY Chamy Enginneer, T&T Green Aug 18 2016 Guest 616 Thumbs Up

Dear All:-

In our LEED CI project the project include Ventilation and A/c Spaces

as per LEED compliance the fan not interlocked with HVAC system is modeled identically such as Ventilation and Exhaust fans, Ceiling fans Evaporative coolers

So please clarify the below issues

1.Can we model A/C space only in Energy simulation (A/C Indoor and Outdoor unit and fans interlocked with HVAC System)
2.Can we Include the Ventilation space in Energy modeling
3.How the fans not interlocked with HVAC systems are modeled
A)Identically
B)Not included in ECB cost saving calculation

Additionally please clarify can we take a advantage of Lighting, Construction, Equipment in HVAC End use not in Lighting and Equipment

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Marcus Sheffer LEED Fellow, 7group Aug 19 2016 LEEDuser Expert 65859 Thumbs Up

1. I would think so since this only covers conditioned space and the unconditioned space would not influence the heating/cooling energy use.

2. You could.

3. Identically.

4. You model the lighting differently in both models and the savings would influence heating/cooling energy use but you can't claim the lighting savings toward the percent needed for heating/cooling. Equipment is usually modeled identically.

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SAMY Chamy Enginneer, T&T Green Aug 22 2016 Guest 616 Thumbs Up

Dear Marcus:-

Thanks for your reply

I agree with lighting saving calculations

But why we need to model our Energy star rated machines identically can we model our equipment in below conditions

1.Basecase - Conventional equipment (Equipment used in similar facility with same capacity)
2.Design case - Actual Equipment (Energy star rated Equipment)

Note:-we just take the savings would influence in heating/cooling due to these equipment not the endues of these equipment

Additionally some ventilation fans are located in Unconditioned spaces can we exclude the energy cost of those fans in HVAC cost because these kind of fans are considered as process load and modeled Identically in LEED NC.

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Marcus Sheffer LEED Fellow, 7group Aug 22 2016 LEEDuser Expert 65859 Thumbs Up

You can model the equipment with some savings and have it influence HVAC the same as lighting. I said it is usually identical, not always.

I would think those fan that are process would not be included in HVAC cost.

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Gabriela Crespo CxA, LEED AP BD+C, O+M Revitaliza Consultores
Aug 05 2016
Guest
327 Thumbs Up

Demonstrate Savings for CRAC Units

Project Location: Mexico

Dear all,

Same project as before, Central Chilled Water System, not in our scope. The only HVAC equipment in our scope are 2 CRAC units for the office's SITES. If we want to demonstrate savings for these units, I understand we should do energy modelling, is it possible to only model the site rooms, or should we model the whole offices?

Thanks!

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Marcus Sheffer LEED Fellow, 7group Aug 06 2016 LEEDuser Expert 65859 Thumbs Up

CRAC units are not regulated in 90.1-2007 so you would have not baseline for comparison. I suppose you could use the 90.1-2010 values for the baseline. You need to show an overall savings so you have to model the whole thing.

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Gabriela Crespo CxA, LEED AP BD+C, O+M Revitaliza Consultores
Aug 05 2016
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327 Thumbs Up

HVAC Appropriate Zoning and Control

Project Location: Mexico

Dear all,

We are working on a Commercial Interiors project, where there is a base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, etc. chiller (not in our scope), and we have a F&C system. We are trying to achieve this credit with the Appropriate zoning and controls option, the form asks to select all that apply, the third option states: "there is no separate method for modulating the HVAC system in response to space demand" , which I suppose would be our case, since we do not have occupant sensors in private offices, nor CO2Carbon dioxide sensors. The new forms do not allow us to verify compliance, but I'm wondering if we will be able to achieve the credit if this is the case.
I hope this makes sense, thanks!

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Michael Smithing Director - Green Building Advisory, Colliers International Aug 06 2016 LEEDuser Member 4228 Thumbs Up

It sounds like you will not be able to get this credit. There are two LEED Interpretations which have added additional requirements, particularly requiring modulation of air flow to meeting rooms in response to space demand. You'll also need occupancy sensors in private offices to reset HVAC to default levels, but you don't need to modulate the airflow in offices.

Check the LI database for additional details.

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Gabriela Crespo CxA, LEED AP BD+C, O+M, Revitaliza Consultores Aug 10 2016 Guest 327 Thumbs Up

Thank you Michael!
Just to make sure we get it right, we would not need to install CO2Carbon dioxide sensors? Only the occupancy sensors?

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Michael Smithing Director - Green Building Advisory, Colliers International Aug 11 2016 LEEDuser Member 4228 Thumbs Up

Whether you use CO2Carbon dioxide sensors will depend on your system. The credit and LI do not require CO2 sensors, they require the system to modulate airflow when the room is not occupied.

In most VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. installations, this would be accomplished with CO2 sensors, but in a CAV system you can use occupancy sensors to achieve the credit requirements.

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Bazeeth Ahamed K M Conserve Green Building and MEP Solutions WLL Oct 26 2016 LEEDuser Member 89 Thumbs Up

Hello
We have a similar case in a project. Chilled water is delivered by district cooling plant. The HVAC system in the fit out is limited to FCUs. Each zone has a seperate FCU. We plan to integrate occupancy sensors with thermostat. The FCUs are high efficient inverter motor driven

We opt to Puruse the credit with Option 1: Prescriptive path, Efficiency requirements are FCUs are not covered in Section 2.9 of CPG.

How do we demonstrate compliance of "Section 2.9: Mechanical Equipment Efficiency requirements – Meet or exceed the minimum requirements for efficiency for listed equipment in the CPG"

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Marcus Sheffer LEED Fellow, 7group Oct 26 2016 LEEDuser Expert 65859 Thumbs Up

I think that if your equipment is not covered you comply by default. Anyone else have contrary experience?

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Michael Smithing Director - Green Building Advisory, Colliers International Oct 26 2016 LEEDuser Member 4228 Thumbs Up

There's another LI applicable to Option 1 that requires the base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, etc. systems serving the space to comply with the CPG. That would apply to your ventilation system as well as the chilled water (and heating if applicable.)

To be honest, I have no idea how the CPG would apply to the district cooling system. As Marcus points out - if the CPG does not cover the equipment in the district cooling system then you should comply by default.

That said, I know that LEED has guidance on how to treat district systems which I've never researched - that guidance may also be relevant.

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Bazeeth Ahamed K M Conserve Green Building and MEP Solutions WLL Nov 29 2016 LEEDuser Member 89 Thumbs Up

Thanks for your inputs. Will keep you posted on the updates when we submit the application

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Francisco Aguirre Senior Engineer Ove Arup and Partners, S.A.
Jul 11 2016
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28 Thumbs Up

LEED Retail CI EAc1.3 zoning and controls

Project Location: Spain

Hi,

I am working on a retail project with a VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system where zoning is performed by variable dampers controlled by thermal sensors in each different thermal zone. Is this option acceptable to meet EAc1.3 zoning and controls requirements?

Thanks

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Marcus Sheffer LEED Fellow, 7group Jul 11 2016 LEEDuser Expert 65859 Thumbs Up

See LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 5273

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Maria Isabel Conde Owner Aqua Terra (Panama) S.A.
Jul 08 2016
LEEDuser Member
236 Thumbs Up

Interpretation Problem

Project Location: Panama

We have a problem with the interpretation of the information necessary to apply for this credit. Credit requirement explain that I have to meet one of the following:

Air handlers that supply at least 60% of the total supply air volume used within the project scope.

or

Mechanical equipment that provides at least 60% of the cooling or heating capacity for the project scope.

In our case, we have 7 WSHPs (all of them part of the scope of work) which none of them supply more of the 60% of the total air/cooling of the space. All WSHPs comply with the efficiencies listed on CPG.

Can we apply for the first 5 points of the credit?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Jul 11 2016 LEEDuser Expert 65859 Thumbs Up

Could you cite the source of the 60% credit requirement? It is not in the credit language. I could not find it in the Reference Guide. Let me know specifically where this is listed as a requirement.

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Maria Isabel Conde Owner, Aqua Terra (Panama) S.A. Jul 12 2016 LEEDuser Member 236 Thumbs Up

Hi Marcus,

It is not in the credit language or in the reference guide. It was told in the ADDENDA 10134, which is write above in the Bird´s eye view:

A typical HVAC installation in an office fit-out has a minimal scope. Often the base building’s mechanical systems supply the space with heating and cooling and ventilation air. What is left to the fit-out team is the distribution system which includes diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light., VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. boxes, and controls. In LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10134, issued on 11/1/11, USGBC clarified the level of HVAC equipment that must be installed to make a LEED-CI or LEED-Retail-CI project eligible for EAc1.3, Option 1, as being one of the following:

Air handlers with Variable Speed Controls complying with the requirements of the Core Performance Guide Section 3.10 that supply at least 60% of the total supply air volume used within the project scope.
Mechanical equipment that complies with the prescriptive efficiency requirements of the Core Performance Guide Section 2.9, and provides at least 60% of the cooling or heating capacity for the project scope.
The project can comply with the requirements of the credit if the project team can show that the relevant criteria have been met for all HVAC systems serving the area within the project scope, whether or not the HVAC systems are installed as part of the tenant scope of work.

We have this doubt with the interpretation because in a past project the reviewer gave us a review who mention exactly the same paragraph of the addenda 10134.

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Jul 12 2016 LEEDuser Expert 65859 Thumbs Up

What this means is that in total the equipment within the scope of the CI project must exceed 60% of either the supply air volume or heating/cooling capacity. It does not mean that any one piece of equipment must be greater than 60%. In your case if the total of all 7 WSHPs meet the 60% criteria then you could qualify.It sounds like this was designed to prevent a CI project with a very limited HVAC scope from earning this credit.

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Maria Isabel Conde Owner, Aqua Terra (Panama) S.A. Jul 12 2016 LEEDuser Member 236 Thumbs Up

Thanks for the reply Marcus.

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Ciaran McCabe METEC Consulting Engineers
Jul 05 2016
LEEDuser Member
551 Thumbs Up

Active Controls with a Fan Coil Unit System

For a Fan Coil Unit system, with outdoor air being provided adjacent to the rear of the unit will the outdoor fresh air rate (from the main AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork.) need to modulate to qualify as "active control" or is it enough for the fan coil unit to switch off the heating / cooling and ramp down to its lowest speed setting. I have read both CI 10242 and 10263 and I am still unsure of the minimum requirements.

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Marcus Sheffer LEED Fellow, 7group Jul 11 2016 LEEDuser Expert 65859 Thumbs Up

As I read it you need either DCV or occupancy sensors. If your system switches off and runs at low speed based on occupancy it sounds like it might qualify.

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Maria Isabel Conde Owner Aqua Terra (Panama) S.A.
Jul 01 2016
LEEDuser Member
236 Thumbs Up

Equipment not list on CPG

Project Location: Panama

Our project has a WSHP bigger than 135000 btuA unit of energy consumed by or delivered to a building. A Btu is an acronym for British thermal unit and is defined as the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu to allow for consumption comparisons among fuels that are measured in different units./h. According to CPG table 2.9.2 the efficiency required for WSHP up to 135000 btu/h is 14 EER and the WSHP of our project has a 14.1 EER.

Since the table doesn't list efficiencies for WSHPs bigger than 135000 btu/h, Do we comply with the credit requirement?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Jul 05 2016 LEEDuser Expert 65859 Thumbs Up

I think so. If the equipment you install is not covered by the standard then I think you comply by default.

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Maria Isabel Conde Owner, Aqua Terra (Panama) S.A. Jul 05 2016 LEEDuser Member 236 Thumbs Up

Thanks Marcus. For the same project we have another doubt. In table 2.9.1 of CPG for unitary air conditioners and condensing units the required efficiency is expressed on EER and SEER. Can we comply with credit requirements achieving just EER or SEER, or are needed both?

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Marcus Sheffer LEED Fellow, 7group Jul 05 2016 LEEDuser Expert 65859 Thumbs Up

Either one should work. The small equipment is usually rated in SEER, so not sure why they have both.

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Maria Isabel Conde Owner, Aqua Terra (Panama) S.A. Jul 05 2016 LEEDuser Member 236 Thumbs Up

Thanks Marcus.

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geoffrey yamasaki senior sustainability analyst mazzetti
May 20 2016
LEEDuser Member
97 Thumbs Up

prescriptive efficiency requirement for purchased heat

If all of my zone equipment and my chillers prescriptively comply with the Core Performance Requirements, but for HHW we have heat exchangers with purchased steam from a district source, then do I need to show that the efficiency of the steam boilers at the plant comply with the Core Performance Requirements? Or is the heating equipment exempt since there are no boilers on site? Thanks for your help.

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geoffrey yamasaki senior sustainability analyst, mazzetti May 23 2016 LEEDuser Member 97 Thumbs Up

Marcus, I have the correct version of the Core Performance Requirements, but it says nothing of purchased heat. I'll submit an inquiry to USGBC.

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Marcus Sheffer LEED Fellow, 7group May 24 2016 LEEDuser Expert 65859 Thumbs Up

I think the heating equipment would be exempt.

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Dipti Talwar Sr. Project Manager Environmental Design Solutions Pvt Ltd
Apr 20 2016
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19 Thumbs Up

EAc1.3

Hi, I have couple of queries regarding EAc1.3 Option 1- Equipment efficiency

1.We are doing a interior fit out project (LEED CI), in which the complete building (100%) will be leased to a single tenant. The landlord has installed all the high side and low side HVAC equipments for eg Chillers, FCU's etc. The chiller meets the advance building code for COP and IPLV. Can the project (CI) claim 5 points under EAc1.3: Optimize Energy Performance—HVAC equipment efficiency?

2. Also,there are certain rooms in the facility which require 24x7 cooling to cool machines for eg. server rooms, lan room, electrical room etc,.These rooms are independently cooled by a split type AC system. Is it required that the split type AC systems installed for such area which require cooling for machines, should meet the efficiencies as required in the CPG?

Thank you.

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Marcus Sheffer LEED Fellow, 7group Apr 25 2016 LEEDuser Expert 65859 Thumbs Up

1. You need to meet all of the Core Performance requirements to earn 5 points.
2. Yes. Especially those since they run so often!

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geoffrey yamasaki senior sustainability analyst mazzetti
Apr 05 2016
LEEDuser Member
97 Thumbs Up

Equipment not listed in the Core Performance Guide

I have a chilled beam system and am unsure which efficiency values to use from the options in the Core Performance Guide to show prescriptive compliance. The equipment should meet efficiency standards, but how would I show it in this case?

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Marcus Sheffer LEED Fellow, 7group Apr 05 2016 LEEDuser Expert 65859 Thumbs Up

You only have to comply with what is covered by Core Performance. If it is not covered you get a free pass.

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Michael Smithing Director - Green Building Advisory, Colliers International Apr 05 2016 LEEDuser Member 4228 Thumbs Up

I'm pretty sure there's a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. that requires the building central system providing the chilled water to meet the efficiency requirements.

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Alan Li
Mar 17 2016
Guest
20 Thumbs Up

Option 2 for LEED CI EAc1.3

Project Location: United States

I'm working on a project that pursues the CI EAc1.3 credit by following Option 2 using ASHRAE 90.1-2007 Section 11. If I understand it correctly, the baseline model not only needs to meet all the requirements in Section 11, but also all the mandatory and prescriptive requirements in each Section of ASHRAE 90.1, such as 6.4 and 6.5 for HVAC. Am I understanding it correctly?

If that's the case, do I have to model both air economizerAn economizer is a device used to make building systems more energy efficient. Examples include HVAC enthalpy controls, which are based on humidity and temperature. and water economizer for chilled water VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. systems for projects located in climate 4a, per ASHRAE 90.1-2007 Section 6.5.1? I'm not sure if Exception a in Section 6.5.1 can be applied to the VAV systems.

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Marcus Sheffer LEED Fellow, 7group Mar 21 2016 LEEDuser Expert 65859 Thumbs Up

You need to meet the mandatory requirements. You can then do either a Section 11 model or an Appendix G model.You do not have to meet the prescriptive requirements when using a performance method. The specific modeling methodology is spelled out in the Reference Guide.

Both Section 11 and Appendix g tell you how to model the baseline. You almost always model the proposed case as designed.

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Alan Li Mar 23 2016 Guest 20 Thumbs Up

Thank you very much for your reply, Marcus!

Yes, I would think that we don't need to meet prescriptive requirements when we use a performance method, i.e. Appendix G or Section 11 energy model.
However, in Reference Guide for LEED CI EAc 1.3 HVAC, it states in Step 6 (pg171) that "For the baseline HVAC model (no modifications to the central plant), change only those items within the project area to the mandatory and prescriptive requirements of the standard". It does look like that we have to meet the prescriptive requirement too?

If that's the case, it comes back to the question that I ask previously about the economizers. Do I have to model air or water-side economizers for VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. systems for projects located in Climate 4a, per prescriptive requirements 6.5.1?

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Marcus Sheffer LEED Fellow, 7group Mar 23 2016 LEEDuser Expert 65859 Thumbs Up

That sentence says that the baseline must meet the mandatory and prescriptive requirements. The proposed only needs to meet the mandatory so you do not have to meet the prescriptive requirements. If they are better than your design you pay a penalty, if worse you get savings. that is the nature of a performance based methodology.

Refer to Section 11 or Appendix G for the requirements in the baseline related to economizerAn economizer is a device used to make building systems more energy efficient. Examples include HVAC enthalpy controls, which are based on humidity and temperature.. For the proposed you are not required to implement all the prescriptive requirements.

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Ciaran McCabe METEC Consulting Engineers
Mar 10 2016
LEEDuser Member
551 Thumbs Up

Pump Performance

Hi,

We have 2 number domestic hot water return pumps (100 watts each). These are the only two pumps we are specifying within the scope of this fit-out.

When we half the flow-rate we cannot reduce the pump kW rating to 30%. We are using a leading manufacturer in pumps. As the overall effect of these pumps will be minimal to the over all project. This seems very onerous to achieve even with new pumps using variable speed drives. Will we lose this credit for not achieving this pump performance ?

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Marcus Sheffer LEED Fellow, 7group Mar 10 2016 LEEDuser Expert 65859 Thumbs Up

Those pumps are not HVAC equipment and are not even regulated by 90.1. So if you don't have any HVAC scope of work you would not be eligible for this credit.

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Ciaran McCabe METEC Consulting Engineers
Mar 04 2016
LEEDuser Member
551 Thumbs Up

Equipment Efficiency EA Credit 1.3

We are trying to document the equipment efficiency for a fit-out we are involved in under Commercial Interiors 2009. On the LEED compliance form it asks us to provide a summary of the mechanical system design calculations e.g. Load calculations, Fan sizing and zone by zone load calculations, critical path supply duct pressure loss calculations, part load condition calculations etc. As the main HVAC plant was selected and sized by others under the landlord base build my question is are we exempt from filling out this section. Im sure we wont be asked to provide detailed calculations for equipment that was not specified within our scope of works. What would we up load here if this section is not relevant to us ? I would be grateful for any opinions on this.

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Marcus Sheffer LEED Fellow, 7group Mar 07 2016 LEEDuser Expert 65859 Thumbs Up

That sounds right to me. Upload a narrative explaining that the information requested does not apply and why.

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Ciaran McCabe METEC Consulting Engineers Mar 07 2016 LEEDuser Member 551 Thumbs Up

Thanks Marcus for your reply and advise.

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Ciaran McCabe METEC Consulting Engineers
Feb 03 2016
LEEDuser Member
551 Thumbs Up

Base Build HVAC Plant Requirements

Hi, I am working on a CI 2009 fit out where the the landlord services such as heating pumps, boilers, AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork.'s and chillers are already installed. We are only specifying and installing the indoor Fan Coil Units. Does all the landlord plant need to comply in terns of efficiency and variable speed or is there any exception since we have no control over this existing plant.

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Marcus Sheffer LEED Fellow, 7group Feb 03 2016 LEEDuser Expert 65859 Thumbs Up

You only need to include the equipment in your scope of work for compliance.

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Ciaran McCabe METEC Consulting Engineers Feb 03 2016 LEEDuser Member 551 Thumbs Up

Thanks Marcus,

It’s the scope that matters. That's what I thought myself however the note below is reference on this website above. Maybe I am misinterpreting something ?

A typical HVAC installation in an office fit-out has a minimal scope. Often the base building’s mechanical systems supply the space with heating and cooling and ventilation air. What is left to the fit-out team is the distribution system which includes diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light., VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. boxes, and controls. In LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10134, issued on 11/1/11, USGBC clarified the level of HVAC equipment that must be installed to make a LEED-CI or LEED-Retail-CI project eligible for EAc1.3, Option 1, as being one of the following:

Air handlers with Variable Speed Controls complying with the requirements of the Core Performance Guide Section 3.10 that supply at least 60% of the total supply air volume used within the project scope.
Mechanical equipment that complies with the prescriptive efficiency requirements of the Core Performance Guide Section 2.9, and provides at least 60% of the cooling or heating capacity for the project scope.
The project can comply with the requirements of the credit if the project team can show that the relevant criteria have been met for all HVAC systems serving the area within the project scope, whether or not the HVAC systems are installed as part of the tenant scope of work.
Another LEED Interpretation, #10135, further clarifies project scope for this credit, noting that "'project scope' refers to all spaces within the LEED project boundary, regardless of whether or not they are included in the project's scope of work. The project can comply with the requirements of the credit as long as all spaces within the 'project scope' satisfy the requirements."

This Interpretation also notes, "Each private office must have its own active controls. Grouping of offices using a single control does not meet the intent of the requirements."

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Ciaran McCabe METEC Consulting Engineers Feb 04 2016 LEEDuser Member 551 Thumbs Up

Hi Marcus, I would be very interested in your opinion on the above. We are very likely to achieve this credit if we can ignore the base build.

Thanks.

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Marcus Sheffer LEED Fellow, 7group Feb 11 2016 LEEDuser Expert 65859 Thumbs Up

Sounds like those interpretations are pretty clear about what must be included to earn Option 1 under this credit. In the future, the more general the question, the more general the answer. Obviously if I knew you were referring to Option 1 then those interpretations apply. Option 2 may be possible depending on the installed equipment.

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Ciaran McCabe METEC Consulting Engineers Feb 11 2016 LEEDuser Member 551 Thumbs Up

No worries Marcus. Yes my original question may have been a bit general. Your response answers my query.

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Chilufya Lombe Sustainability Consultant Solid Green Consulting
Jan 21 2016
Guest
453 Thumbs Up

Natural Ventilation

Project Location: South Africa

Good day, we have a project that is naturally ventilated. ASHRAE 90.1 2007 states that the energy cost budget method cannot be used for designs with no mechanical systems. We have all the calculations to prove natural ventilation will work but it appears we cannot target any points under HVAC. Is there a way for projects with natural ventilation to target points in the HVAC category of Eac1?

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Marcus Sheffer LEED Fellow, 7group Jan 21 2016 LEEDuser Expert 65859 Thumbs Up

The accepted method for projects to claim savings for natural ventilation is contained in one of the appendices to the Advanced Energy Modeling Guide for LEED Technical Manual.

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Chilufya Lombe Sustainability Consultant, Solid Green Consulting Apr 20 2016 Guest 453 Thumbs Up

Hi Marcus, how does this work when only a section of the building is mechanically ventilated? Would we use the guidance in the Advanced Energy Modelling Guide for the naturally ventilated spaces and Core Performance guide for the mechanically ventilated portion?

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Marcus Sheffer LEED Fellow, 7group Apr 25 2016 LEEDuser Expert 65859 Thumbs Up

I don't think you can mix the performance path with a prescriptive path.

You could model model both systems in different parts of the building.

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Dec 10 2016
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