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 GBCI 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

    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.

297 Comments

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Steve Gross Interface Engineering
Mar 27 2014
LEEDuser Member
15 Thumbs Up

Option 1: Existing Equipment

I have read Interpretation #10134 and 10135, but based on some of the comments below, I would like some additional confirmation. Does new system-level mechanical equipment that serves 60% of the space need to be installed (to pursue item 1 or 2 in #10134), or can this apply to existing systems serving new zone-level equipment (i.e. 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. reheat boxes)? Otherwise item 3 will have to be pursued, meaning that existing equipment will have to meet all relevant criteria.

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Ante Vulin Sustainability Manager, YR&G Apr 11 2014 LEEDuser Expert 892 Thumbs Up

Steve, you must install air-handlers supplying 60% of the flow or heating/cooling equipmentThe equipment used for cooling room air in a building for human comfort. supplying 60% of heating/cooling capacity to pursue the first two options under Intepretation #10134. If the scope of work for the LEED CI fitout only includes new ducts and 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, then you have to show that existing or base-building equipment meets the requirements in the CPG.

Post a Reply
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MM K
Mar 14 2014
Guest
898 Thumbs Up

Tenant space fan & pump sizing

We are a bit confused as to the meaning of space fan and pump sizing? Could anyone please offer some clarification?

Thanks!

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 35115 Thumbs Up

Could you please indicate where these terms have been referenced for context?

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MM K Mar 14 2014 Guest 898 Thumbs Up

Hi Marcus,

It is on the online form, under Equipment Efficiency, under section 1.4-Mechanical System Design Criteria

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 35115 Thumbs Up

Which version of the form?

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MM K Mar 14 2014 Guest 898 Thumbs Up

Version4

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 35115 Thumbs Up

I can't find it in the v4 form under EAc1.3? Are you in Core Performance?

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 35115 Thumbs Up

This section of Core Performance deals with designing the mechanical systems. There are a series of steps outlined in this section which must be followed and then documented to demonstrate compliance. What needs to be done is documented in the Core Performance document which you need to have a copy of to be able to demonstrate compliance.

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MM K Mar 14 2014 Guest 898 Thumbs Up

We are looking at Option 1 - Equipment Efficiency under Core Performance Guide
The reason is that all mechanical systems are in the basebuild and we were wondering whether the kW of 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. fan and pump sizing should be included or left blank? The system is a chilled ceiling system.

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 35115 Thumbs Up

Now I see it. Only those components within the tenant scope of work need to be included. Anything within the base building systems that is already in place does not need to be addressed. This line clearly indicates tenant fan and pump sizing. If the fans and pumps are already there and are not part of the tenant scope of work leave it blank or indicate NA.

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MM K Mar 14 2014 Guest 898 Thumbs Up

Thanks a lot Marcus! Much appreciated! Does the same apply for Table EAc1.3-1 under Criteria 2.9 regarding variable speed control?

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 35115 Thumbs Up

I think the same principle applies - if it is not in the tenant scope of work you do not have to demonstrate compliance.

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MM K Mar 14 2014 Guest 898 Thumbs Up

Thank you Marcus!

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Thiago Bondini
Mar 11 2014
LEEDuser Member
242 Thumbs Up

Project Scope and Tenant Scope

Another one I can´t quite get my head around.
Our client will be the sole tenant in a small commercial building. The owner has provided a VRF system complete with the condensers and evaporators (the space has never been occupied).
Our preliminary review suggests that the system will comply with the ASHRAE and NBI requirements.but if the tenant does nothing more than install proper zone ductwork and controls can they achieve the Equipment Efficiency portion of this credit?

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Ante Vulin Sustainability Manager, YR&G Apr 11 2014 LEEDuser Expert 892 Thumbs Up

Thiago, that is correct - you would be meeting the credit requirement under the third option of interpretation #10134. But note that you must also provide load calculations that meet the requirements of the credit.

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Steve Gross Interface Engineering
Mar 06 2014
LEEDuser Member
15 Thumbs Up

Option 2: ASHRAE 90.1-2007 Section 11?

Even though the credit language does not state it explicitly, I read "reduce design energy cost compared with the energy cost budget for regulated energy components" to mean "reduce the design energy cost compared with the energy cost budget for regulated components as calculated using ASHRAE 90.1-2007 Section 11". Is this correct?

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Marcus Sheffer LEED Fellow, 7group Mar 06 2014 LEEDuser Expert 35115 Thumbs Up

See the Reference Guide for the details. You are allowed to use Section 11 or Appendix G for these calculations.

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MM K
Feb 27 2014
Guest
898 Thumbs Up

Base build pumps and fans

Hello,
If all central pumps and fans are base build, does section 3.10 of the form need to be completed?
Also, does the 'Total 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. fan and pump sizing' under section 1.4 have to be filled or can that be left blank?

Thanks!

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Dylan Connelly Mechanical Engineer, Integral Group Mar 04 2014 LEEDuser Expert 6117 Thumbs Up

Check 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., #10135 & #10134. If the equipment is the primary means of serving the space it needs to be included.

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Ronald Dean Sumac Inc.
Feb 14 2014
LEEDuser Member
813 Thumbs Up

Compliance with Core Performance Guide Sections

Hello everyone,

I'm working in a smal project (just 2 floors) that is naturally ventilated overall.
The thing is that we're thinking about installing air conditioning equipment for only two small offices, maybe two split units and that's it.
So, my question is: can we earn this credit even if we're not going to install equipment for all the project?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Feb 17 2014 LEEDuser Expert 35115 Thumbs Up

You have to install mechanical equipment to earn the credit. However I would suggest that you not let LEED dictate something stupid just to earn a point.

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Sunayana Jain
Jan 31 2014
LEEDuser Member
40 Thumbs Up

Constant Volume RTUs and Energy Star Label

I am not clear from CPG whether 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. is required for Option1 (Equipment Efficiency - 5 points). I have Constant Volume RTUs 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.. All of them have supply fan less than 5 HP. Can this qualify under option1?
Also latest CPG states that "Packaged unitary equipment shall meet the minimum efficiency requirements in table 2.9.1 and 2.9.2 and be Energy Star labeled." I used to think that either the packaged system has to qualify the above tables or Energy Star but not both. Any views will be appreciated.

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Sunayana Jain Feb 03 2014 LEEDuser Member 40 Thumbs Up

I am looking for forum's responses quickly. Your views will be appreciated.

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Marcus Sheffer LEED Fellow, 7group Feb 17 2014 LEEDuser Expert 35115 Thumbs Up

Free and fast, pick one. :-)

As long as your fan motors are less than 5 HP they do not need to comply so you should be fine under option 1.

The previous version of CPG also says "and". For an international project I would think that if you can demonstrate that it meets the efficiency requirement it would not necessarily have to also be ES labeled.

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Sunayana Jain
Jan 20 2014
LEEDuser Member
40 Thumbs Up

One RTU not qualifying the prescriptive requirements

Hi, I am working on a LEED CI project in which HVAC equipments (serving 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 not being replaced ( 5 RTU units), one of the RTU unit is very old and does not qualify Efficiency requirements of Table 6.8.1A. Based on ID#10134, I am understanding that all these 5 units still need to qualify table 6.8.1A and "New Building Institute's Advanced Buildings Core performance" requirements for Option 1(equipment efficiency - 5 points). Is this correct? Can I consider Option -2 to prove 15 % savings?

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Dylan Connelly Mechanical Engineer, Integral Group Jan 23 2014 LEEDuser Expert 6117 Thumbs Up

Sounds like you're asking if you can take 5 points from the prescriptive path (option 1) and 5 points from performance path (option 2).

The answer is no. You can do option 1 or option 2. Not a partial of both.

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Sunayana Jain Jan 23 2014 LEEDuser Member 40 Thumbs Up

Dylan,
Thank you for your reply.
My situation is: One of the existing RTU (installed in 1999) 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. does not qualify CPG requirements (neither qualify efficiency requirements of Section 6.4).
My question is: Can this project still be eligible for Option 1 - 5points?
I am not planning to apply through both the options. In case, I am not eligible for Option 1, can I go with option 2 if I am able to prove 15 % savings over ECB energy model?

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Dylan Connelly Mechanical Engineer, Integral Group Jan 24 2014 LEEDuser Expert 6117 Thumbs Up

Sunayana,
Read further down and we talk about your condition. Even if the unit is existing it needs to comply. But also note per 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, only systems that are supplying 60% of the air or heating/cooling need to comply.
Yes if you don't comply with option 1 you can try option 2 if you can get your model to show 15% better than code.

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Sunayana Jain Jan 27 2014 LEEDuser Member 40 Thumbs Up

Thanks Dylan.

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Sunayana Jain Jan 30 2014 LEEDuser Member 40 Thumbs Up

Dylan,
I am not clear from CPG whether 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. is required for Option1 (Equipment Efficiency - 5 points). I have Constant Volume RTUs 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.. All of them have supply fan less than 5 HP. Can this qualify under option1?
Also latest CPG states that "Packaged unitary equipment shall meet the minimum efficiency requirements in table 2.9.1 and 2.9.2 and be Energy Star labeled." I used to think that either the packaged system has to qualify the above tables or Energy Star but not both. Any views will be appreciated.

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Dylan Connelly Mechanical Engineer, Integral Group Feb 17 2014 LEEDuser Expert 6117 Thumbs Up

Are the constant volume RTUs the new units you've installed?
It is typically pretty hard to find RTUs that are energy star labeled - perhaps a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide is appropriate to clarify you are meeting the efficiency requirements at least.

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Sunayana Jain Feb 17 2014 LEEDuser Member 40 Thumbs Up

Thanks Dylan. Constant Volume RTUs are already existing ones. No change is being made to the HVAC portion 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..

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TOMAS URIBE PROJECT MANAGER SOLUCIONES ENERGETICAS SOSTENIBLES
Dec 12 2013
LEEDuser Member
289 Thumbs Up

Simulation approach strategy.

Hello Marcus.

We have a project that will be applying for LEED certification under CI. The project is located on 4th floor within an office building with 5-floors. The building is served by a common HVAC system (air cooled chillers, and pumps), everything else will be in the design as part of the tenant development (interior HVAC, lighting etc).

For the Proposed Design the simulation strategy is to simulated only the CI portion of the building by spliting the Chiller capacity for the CI project area. COP wil be simulated with chiller nominal value. Other systems such as pumps will be sized for the CI load.

For the Budget design the simulation will be based on ASHRAE chapter 11 for the CI portion of the building as well.

Do you think this approach is valid for the GBCI reviewers?

Any advise would be appreciated.
Thanks

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Marcus Sheffer LEED Fellow, 7group Dec 31 2013 LEEDuser Expert 35115 Thumbs Up

As I have said before we did something similar for an NC project many years ago and our methodology was acceptable then (here is the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide - ID#5496, 11/02/2004). However, the ID+C Reference Guide is pretty clear that you need to model the whole building if it has a central plant. I would still advocate that there is a way to account for this without having to model the whole building but I am not sure if the reviewers would agree. If you want a definitive answer you should submit 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. (might want to check the existing ones first). If you decide to go ahead make sure you thoroughly explain your methodology and provide any calculations used to proportion the loads, etc. to the reviewer.

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Steven Beccia Mechanical Engineer Clark Nexsen
Dec 11 2013
Guest
67 Thumbs Up

High performing existing baseline building.

Hello All,

I am looking to get some clarification or consensus regarding modeling the baseline HVAC systems for EAc1.3.

My specific scenario is that we have a core and shell building, under construction, that recently completed the LEED design portion of CS, and is showing considerable savings over ASHRAE Baseline.

Next we are starting the certification process for the tenant fitout under CI.

In the previous comments, it has been suggested that since this credit only counts any savings from the newly designed HVAC systems, if any, for the fitout, the 'existing' (CS) building envelope and systems that are untouched should be modeled identically in both cases.

If this statement holds true, then for my specific building scenario, since we are not modifying the central plant or central air distribution - these were sized and designed for the CS building - what strategies, if anything, can i employ in the CI design building or baseline building to show savings?

Is this design scenario appropriate to try and show savings? The tenant fitout is approximately 1/3 of the total square footage of the building, and the rest of the building is not within the project scope and has not been leased as of now.

It is a DX 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. water cooled building, and the basic system differences between the CS design and the fitout design is that for the fitout, the VAV zones and interior loading have been defined, where as in the CS design the VAV zones and loading were assumed.

Is that enough of an HVAC systems change that I go through the process to select the appropriate baseline HVAC system via ASHRAE chapter 11 HVAC systems map (Water cooled, electric heat, non-residential) and model the baseline per chapter 11?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Dec 31 2013 LEEDuser Expert 35115 Thumbs Up

You can get credit for an efficient central plant. There are also scenarios in the modeling protocol to get credit for envelope improvements in some cases. The baseline system is defined by Section 11 or Appendix G in all cases. The best guidance on how to do this modeling is in the ID+C Reference Guide so do not rely on this forum for definitive guidance in all cases. This especially applies to any advice i may have provided. :-)

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TOMAS URIBE PROJECT MANAGER SOLUCIONES ENERGETICAS SOSTENIBLES
Nov 27 2013
LEEDuser Member
289 Thumbs Up

Energy Model Scope - Shared HVAC Plant

Hello there.

We have a project that will be applying for LEED certification under CI. The project is located on 4th floor within an office building with 5-floors. The building is served by a common HVAC system: air cooled chillers. We have the following doubts for EAc1.3 using the option # 2-ASHRAE APPENDIX 11:

- Is it necessary to simulate the whole building? The LEED Guide for ID+C indicates that the building segment served by the common HVAC system must be simulated (in this case, the whole building). We think that simulating the whole building is impractical.

- If we have to simulate just the floor that is under certification, how do we model the HVAC system in the design model? The chilled water is metered and billed separately for each tenant within the building.

How do we assign the system type in the baseline case model?

- Marcus, in other comment you wrote:

“Having to model the whole building with a central plant is a major problem for the project we are working on. We wrote a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide many years ago which was approved for NC where we proportioned the load on a central plant to model an addition. The same methodology could be applied for a CI space IMO.

The biggest problem is often determining the existing conditions beyond your scope especially in multi-tenant spaces.”

Can you tell us the CIR number so that we can look for it and try to understand this manner in a better way?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Nov 27 2013 LEEDuser Expert 35115 Thumbs Up

Our situation was a bit simpler but here is the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide - ID#5496, 11/02/2004.

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Thomas Nichols LEED AP (O+M) 4 Elements Group
Nov 12 2013
LEEDuser Member
284 Thumbs Up

Core Performance Compliance New Air-handler- Existing Chiller

If we specify a new air handler that uses steam and chilled water from existing systems, do these systems need to comply with the CPG efficiency requirements? We are looking to use Option 1.

The air handler is a 5 HP 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. unit so it would just need a variable frequency drive, correct?

Thank you,

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Marcus Sheffer LEED Fellow, 7group Nov 27 2013 LEEDuser Expert 35115 Thumbs Up

I don't think the existing systems would need to comply with the equipment efficiency requirements (2.9).

The 5 HP 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. has to meet the criteria in 3.10. It is not just having a VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously.. It requires that the control will result in fan motor demand of no more than 30% of design wattage at 50% of design flow.

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Emily LaChapelle
Sep 12 2013
Guest
15 Thumbs Up

Points for High-Efficiency HVAC Motor

How and in what way can points be obtained specifically related to a high-effiency HVAC motor in a retro-fit scenario?

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Marcus Sheffer LEED Fellow, 7group Sep 14 2013 LEEDuser Expert 35115 Thumbs Up

It might help contribute to earning points under Option 2.

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Emily LaChapelle Sep 19 2013 Guest 15 Thumbs Up

Thank you, Marcus. Can you elaborate on the different areas where it might be applicable for us us to obtain points specifically related to the motor as well? I have been reading about points attributed to VSD, IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. . . . any others?

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Marcus Sheffer LEED Fellow, 7group Sep 19 2013 LEEDuser Expert 35115 Thumbs Up

Retrofitting a high-efficiency motor will not earn any points in and of itself. A high-efficiency motor retrofit will primarily save energy due to its high-efficiency relative to a standard motor. If you add a VSD it saves more energy. This could contribute to the energy saving percentages needed for this credit under Option 2 but will not get you there by itself. Not sure how it contributes to any IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. credits?

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Jatuwat Varodompun Dr Green Building Soultion
Sep 05 2013
LEEDuser Member
821 Thumbs Up

Core performance path

We plan to option 1 equipment efficiency.
1 We have 500,000+ 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 VRF compressor which is specified in CEE Tier two as "NA". Does it mean the we automatically comply with the requirement?

2 For the VSD capability of >5hp motor, does it cover evaportor fan, condeser fan, and all HVAC pumps.

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Marcus Sheffer LEED Fellow, 7group Sep 23 2013 LEEDuser Expert 35115 Thumbs Up

1 - Did you check to see if there are any addenda to Core Performance that may have addressed VRF systems?
2 - Looks like it certainly applies to all of the pumps. It would apply to the fan within the indoor heat pumps but not apply to the fan in the outdoor unit.

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María Fernanda Aguirre Architect LEED AP BD + C - LEED AP ID + C Renato Miranda and Associates
Aug 19 2013
Guest
165 Thumbs Up

Passive House Certified Component vs Energy Star Products

Hi, I am currently working on an LEED for Commercial Interiors Project and the HVAC Engineer has just heard about some ventilation units with heat recovery which are certified as Passive House Components (by the Passive House Institute) but are not Energy Star Certified. What worries us is that we want to pursue credit EA c1.3 through the prescriptive option and it is requiered that equipment (rated of course) must be Energy Star certified or meet its criteria.
Does some one knows if Passive House components meet Energy Star criteria or how can I get comparative information between them?. Thanks so much!!!!

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Marcus Sheffer LEED Fellow, 7group Aug 29 2013 LEEDuser Expert 35115 Thumbs Up

It does not appear as if Energy Star rates air-to-air heat exchangers. If the equipment is not rated by Energy Star it is exempt I believe.

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Catalina Caballero Sustainability Coordinator JALRW Eng. Group Inc.
Aug 14 2013
LEEDuser Member
1321 Thumbs Up

Option 2: Insulation for Baseline and Proposed

Under "LEED Project Submittal Tips: Commercial Interiors 2009", the guide is referencing to Table G3.1-5(F) when applicable for baseline and propose values consistent with Appendix A. Is this correct?

http://www.usgbc.org/resources/leed-project-submittal-tips-commercial-in...

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Marcus Sheffer LEED Fellow, 7group Aug 14 2013 LEEDuser Expert 35115 Thumbs Up

In general with an existing building you model the baseline with the existing conditions and the proposed as designed. If you added insulation you can take credit for it.

For this particular credit under Option 2 you can only count any savings from HVAC systems and equipment so I have always assumed the other parameters like lighting envelop, etc. must be identical so that there is no savings generated from these strategies. Maybe I am missing something?

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Catalina Caballero Sustainability Coordinator, JALRW Eng. Group Inc. Aug 14 2013 LEEDuser Member 1321 Thumbs Up

Then this "LEED Project Submittal Tips: Commercial Interiors 2009" by GBCI is confusing me because is saying this, unless is incorrect.

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Tony Ricketts Mechanical Engineer, CJL Engineering Aug 14 2013 Guest 151 Thumbs Up

Victor & Catalina,

The "Tips" may have just mis-worded the sentence to which you are referring. In fact, as I read through the Tips, I don't quite see where it says to use the existing wall in the proposed case model.
Option 2: Performance Path: ASHRAE 90.1, Appendix G, Envelope; 2nd & 3rd notes read;
"Be sure that the proposed case U-values are consistent with the various wall and roof construction assemblies listed in Appendix A of ASHRAE 90.1."
"Don't forget to model the baseline case exterior wall, roof, floor/slab constructions and reflective roof as required by ASHRAE 90.1 Table G3.1-5 and Table 5.5"
Neither of these Tables appear to say you cannot take credit for your design to add insulation. Please let us know what section of the "Tips" you are reading, I seem to be overlooking it.

I feel like this is one that would be worth attempting the way Marcus described, for the first LEED submission, at least. I believe Marcus is correct in his assertion of the LEED credit's "intent", but submitting under these circumstances (first submission to GBCI) gives you the opportunity to get direct/specific feedback from the LEED reviewer about your project, and the opportunity to make revisions.

It seems as though you believe that the "spirit" of LEED would want you to take credit for your effort to insulate the walls, and Marcus agrees with this inclination.

I think if I were in your situation, I would just explain the rationale to the reviewer in a narrative. Site the sections of 90.1 that allow modeling of the existing condition as baseline case, and utilizing the designed envelope as proposed case.

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Catalina Caballero Sustainability Coordinator, JALRW Eng. Group Inc. Aug 14 2013 LEEDuser Member 1321 Thumbs Up

PROPOSED: "Be sure that the proposed case U-values are consistent with the various wall and roof construction assemblies listed in Appendix A of ASHRAE 90.1."
Therefore refering to actual design values (concrete wall with insulation);

BASELINE: "Dont forget that the existing envelope conditions for baseline case should be modeled per the requirements of Ashrae 90.1 Table G3.1-5 (f)" Old existing conditions on the baseline (solid concrete wall-warehouse)

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Tony Ricketts Mechanical Engineer, CJL Engineering Aug 15 2013 Guest 151 Thumbs Up

Agreed.
The way I interpret those statements:

Proposed: Confirm that your Proposed Case (after renovation) wall construction overall U-valueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value. is calculated using the U/R-values provided in Appendix A for each "layer" of material making up the assembly. And, always remember to account for insulation between studs, if applicable, to match the R-value of that layer in your wall assemblies, per Appendix A.

Baseline: Per the note in Table G3.1-5f, model the Baseline Case envelope as the existing (pre-construction) assemblies. Again, match the U-values for each layer with Appendix A.

Again, however you interpret the codes, include your justification in the narrative. This way you can state why you proceeded as you did, and a reviewer will either understand/agree with your choices, or let you know what they feel you should revise.
In the end, it seems, it's always up to the Authority Having Jurisdiction. All you can do is present the most logical rationale available to back up your assumptions, and hope they agree.
In this case, both Marcus and I feel you should be able to take credit for your effort to insulate the walls.

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Catalina Caballero Sustainable Designer JALRW
Aug 14 2013
Guest
37 Thumbs Up

Insulation

Our project consist in a conversion from a warehouse to a university. but only part of the univeristy is being certified. Obviously as a warehouse the building didnt have any type of insulation for which in the renovation insulation was added. I see that under the refence guide, the propose needs to be modeled with the existing envelope, however, it does not really make sense to us that we could not take advantage of the insulation given the fact that the boundary is quite big and we are using a big percentage of the envelope being modified.

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Marcus Sheffer LEED Fellow, 7group Aug 14 2013 LEEDuser Expert 35115 Thumbs Up

I assume you are referring to ASHRAE 90.1-2007 Appendix G, Table G3.1-5(Baseline)(f) which allows the modeling of the existing envelope in the Baseline. You model the proposed as it was designed, not as it was previously existing. This particular credit has nothing to do with insulation levels so in the future please post under the appropriate credit.

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Catalina Caballero Sustainable Designer, JALRW Aug 14 2013 Guest 37 Thumbs Up

Maybe I didnt title it correclty but Im refering to Option 2, where for modeling the propose alternative the guide says: use existing values. My existing values are a warehouse with solid concrete walls without insulation, but after renovation is finished the building will have new insulation, therefore not really sure which values to used for the baseline and the proposed envelope for the modeling.

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Catalina Caballero Sustainable Designer, JALRW Aug 14 2013 Guest 37 Thumbs Up

Please refer to the "LEED Project Submittal Tips: Commercial Interiors 2009" where says that Table G3.1-5(Baseline)(f) is applicable

http://www.usgbc.org/resources/leed-project-submittal-tips-commercial-in...

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Marcus Sheffer LEED Fellow, 7group Aug 16 2013 LEEDuser Expert 35115 Thumbs Up

Yep I saw that and it is also being discussed in the post above this thread. Just because it is written does not mean it makes any sense!

What does not make sense to me is why it is written there. For this particular credit you can only claim savings related to HVAC systems and equipment. Therefore it only makes logical sense that any other building parameter must be held neutral in the energy models or they would influence the savings.

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Tony Ricketts Mechanical Engineer CJL Engineering
Aug 12 2013
Guest
151 Thumbs Up

Option 1, Equipment Efficiency - Reuse of Existing Equipment

Hi all,

I have a tenant fit-out project served by water source HPs.
There is a building standard for the equipment (Building owns/maintains equipment, and regulates unit make/model used in 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.). The building calls for the "high efficiency" model heat pumps to be used.

We are replacing nearly all of the units serving the space (roughly 15), but 4 have been recently replaced, work out for the new zoning, and the owner & tenant would like to keep them for reuse.

Do these existing systems need to meet the CPG guidelines for unit efficiency?
The "high efficiency" models from a few of years ago were great for their time, but technically do not quite meet the CPG requirements.
Do we have to replace these units to meet the LEED requirements?
Or are the requirements only for newly installed equipment?

Seems like a waste to remove good units to replace them with something that is only slightly more efficient.

Thanks,
Tony

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Dylan Connelly Mechanical Engineer, Integral Group Aug 13 2013 LEEDuser Expert 6117 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. 10134. Only systems that are supplying 60% of the air or heating/cooling need to comply.

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Tony Ricketts Mechanical Engineer, CJL Engineering Aug 14 2013 Guest 151 Thumbs Up

Thanks Dylan!
This is very helpful.

One other question I'm a little uncertain about:
Since the ventilation air provided to the space is part of the base building systems, should I include that in the capacity percentages as I'm verifying the 60/40 split in new vs old equipment?

(I ask this way because in "most" projects the OA is supplied through a larger central building unit, over which a tenant has very little control. Also, estimating the prorated load of the unit could be difficult, depending on the building owner's records. In our case, the OA is provided through 5 CAV WSHPs mounted above the ceiling in 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.. These units "could" be replaced, if necessary, but it is not in the tenant's construction budget.)

Thanks for the help!
Tony

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Dylan Connelly Mechanical Engineer, Integral Group Aug 16 2013 LEEDuser Expert 6117 Thumbs Up

Tony,
The way I read the 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. the 60% rule means only single pieces of equipment that supply 60% of the space's capacity. However, it could be that if the same type of system is serving the whole space or most of the space they would need to comply as well. It's not clear.

Another good point you made is that the interpretation doesn't say anything about ventilation systems. You could assume the 60% rule there as well to be conservative.

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Catalina Caballero Sustainability Coordinator JALRW Eng. Group Inc.
Aug 06 2013
LEEDuser Member
1321 Thumbs Up

Percent Annual HVAC Energy Cost Reduction

Which Cost reduction equation should be used on template when cooling plant has been updated with a high efficiency chiller and therefore proposed has been modeled including all the areas that this chiller serves, showing savings for both the project areas and out of leed boundary areas? If we go with the Equation 1 our percentage comes up to be huge (more than 100%) because the difference on space cooling is high (again for both in and out of leed boundary areas) and the difference of project area and total segment area is also high. If we use equation 2 on the other hand is a more reasonable percentage 33%, however alternate baseline case was not model.

Thanks

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Mary Ann Santos
Jul 29 2013
LEEDuser Member
1965 Thumbs Up

Damper actuator for operating HVAC systems

Hi, does a damper actuator qualify as an active control?

Per CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide#10242, "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 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 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."

We have a VRF system and installed actuators with temperature sensors connected to BMS. The way it works is that the damper actuator operates air control dampers in ventilation and air-conditioning systems. These are connected to temperature sensors that automatically triggers the BMS to adjust the HVAC system according to the temperature readings. When there is no people in the space, the temperature sensor connected to the BMS adjust the air conditioning system. Will this suffice as an active control?

Thank you in advance.

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Dylan Connelly Mechanical Engineer, Integral Group Aug 13 2013 LEEDuser Expert 6117 Thumbs Up

Does the damper control the total air to the room or just the ventilation supply to the back of the VRF unit?

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Mary Ann Santos Aug 28 2013 LEEDuser Member 1965 Thumbs Up

Hi Dylan, the motorized damper control the ventilation supply back to the VRF unit. Will this suffice?

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Dylan Connelly Mechanical Engineer, Integral Group Sep 03 2013 LEEDuser Expert 6117 Thumbs Up

That is good. You can use the motorized damper to reduce the outside air to the spaces when a sensor says there is no one in the space. Or use a CO2Carbon dioxide sensor. You would need to have a motorized damper for each space.

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Mary Ann Santos Sep 04 2013 LEEDuser Member 1965 Thumbs Up

Many thanks!

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