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.

355 Comments

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Carla Lopez Director of Valuation & Advisory CBRE
Apr 20 2015
LEEDuser Member
29 Thumbs Up

Portable Air Conditioning.

Dear all,
For an office building project we will be using a PORTABLE AIR CONDITIONER to cool the IT room; the unit has a cooling capacity of 12,000 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. (Reference:
http://www.comfortstarusa.com/products/mpk12-410/).
In order to comply with CI EAc1.3, do we need to add or list this equipment?
Could anyone please offer some clarification?
Thanks!

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Marcus Sheffer LEED Fellow, 7group Apr 20 2015 LEEDuser Expert 52887 Thumbs Up

It is HVAC equipment so I think yes.

Post a Reply
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Yaser Al Sharif
Apr 08 2015
Guest
101 Thumbs Up

Pressure loss calculation

Project Location: Jordan

We are registed for commercial interior rating system , the system installed in our project is vrv system, in order to comply with optimize energy performance EAC1.3 , critical path supply duct pressure loss ,so should i calculate duct pressure losses for all ducted indoor units or only for fresh air indoor units despite that the fresh air unit is connected to vrv system .

Thanks

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Marcus Sheffer LEED Fellow, 7group Apr 08 2015 LEEDuser Expert 52887 Thumbs Up

Could you be more specific about which Option you are pursuing under this credit and where the item you are referencing is mentioned?

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Yaser Al Sharif Apr 09 2015 Guest 101 Thumbs Up

refering to optimize energy performance option 1 - equipment efficiency - it is mentioned in the requirments of this path to comply the advanced building core performance guid sections 1.4,2.9 and 3.10.
for this path mechanical system design calculations must be included, the load , fan sizing , critical path supply duct pressure loss.. so my question is should i calculate critical path supply duct pressure loss for all indoor units or only for fresh air units.

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Marcus Sheffer LEED Fellow, 7group Apr 09 2015 LEEDuser Expert 52887 Thumbs Up

I think it is referring to all of the supply ducts.

Post a Reply
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Jonathan Caisido Green Technologies
Feb 16 2015
Guest
5 Thumbs Up

CPG - Efficiency Compliance

Project Location: United Arab Emirates

Hello,
I would like to know on how to comply CI EAc1.3 if using base build Chilled Water Fan Coil Units. What is the alternative to verify the efficiency compliance on Core Performance Guide if the chiller's efficiency is not available.

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Marcus Sheffer LEED Fellow, 7group Feb 17 2015 LEEDuser Expert 52887 Thumbs Up

If the chiller's efficiency in not listed in Table 2.9.5 see note b in that table and then see the link at the bottom of the page for more chiller tables.

http://www.advancedbuildings.net/reference-materials/reference-materials...

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Jonathan Caisido Green Technologies Feb 18 2015 Guest 5 Thumbs Up

Thanks Marcus but how about Chilled Water Fan Coil Equipment Efficiencies since these are not covered under Core Performance Guide? Do we really need to collate the Landlord / Base Build systems together with the project's HVAC systems to comply with this credit requirement? Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Feb 18 2015 LEEDuser Expert 52887 Thumbs Up

Chilled water fan coil units do not really have a rated efficiency. It is the efficiency of the chiller itself that is in CPG 2.9.

Yes it appears that way. The whole system design is what is addressed by sections 1.4 and 2.9.

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Priyadarsi Das Engineer - Sustainable Design LEAD Consultancy & Engineering Services(I) Pvt Ltd
Feb 04 2015
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2 Thumbs Up

Datacentre Requirements

Project Location: India

Project Description:

The project is approximately 3.0 lack Sft which is G+10 floors and going for LEED CI rating. The 9 floors in the project is office space and remaining one floor is dedicated to labs / data centre. For Equipment efficiency credit – prescriptive approach, the project is meeting the advance building code for COP and IPLV of chillers. The project is going for Air-cooled chillers (7 nos) for labs/ data center and water-cooled centri for other floors i.e. office space. Below are the queries related to the same:

1. Due to the constant temperature in labs and data centre, is it recommended to opt for VFD’s in order to meet the requirement for equipment efficiency points? The temp maintained will be around 18 to 20 deg C
2. For Data centre space the project is also going for IRC(In-Row coolers). Does LEED have any specific reference to verify and check the parameters for IRC system w.r.t LEED for CI? Can In-Row Coolers be considered as PAC unit to meet the LEED CI requirements in Advanced Building Code?
3. Is "Zoning Control" applicable for:
a) data center floors
b) labs/ data center without windows(or windows without vision)
c)un-occupied areas in the floor?

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Marcus Sheffer LEED Fellow, 7group Feb 11 2015 LEEDuser Expert 52887 Thumbs Up

1. The equipment efficiency strategies are prescriptive in nature so you just need to do the minimum requirement. Anything beyond that should be evaluated on its merits in the context of your project. As I recall the 3.10 VSD requirements refer to motors.
2. I don't think these systems are covered. If a system is not covered I do not think you can use the prescriptive approach.
3. These guidelines were clearly not written to cover a data center of lab space.

Off the top of my head it appears like you would need to follow the performance path.

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Gustav Alfaro Mechanical Engineer
Jan 26 2015
LEEDuser Member
189 Thumbs Up

Optimize Energy Performance -HVAC-

Hi, I have a couple of questions regarding EAc1.3

1. Our HVAC design includes VRF systems that are compliant with sections 1.4 and 2.9 of the Core Performance Guide, but those systems don't have variable control of air (required by section 3.10) However, the standard has an exception if the fans motor horsepower are smaller than 5hp which is our case. Is that an allowable exception to be used for submittal review purposes?

2.We are trying to pursue the zoning and controls strategy; is it correct if we use occupancy sensors for independent offices, conference rooms, etc. that turn on and off the units based on occupancy but with no setback and with no demand-controlled ventilation strategies?

Thank you in advance

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Michael Smithing Director - Green Building Advisory, Colliers International Jan 26 2015 LEEDuser Member 2860 Thumbs Up

I can only comment on the second question. There are two LEED Interpretations on this topic (#10242 and #10263). The second requires demand controlled ventilation in conference rooms, but not individual offices. We've successfully appealed this on CI a project with a base building CAV system by pointing out this approach would increase rather than decrease energy, but this only works because the building has not installed variable frequency controls on the 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. drives.

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Gustav Alfaro Mechanical Engineer Jan 26 2015 LEEDuser Member 189 Thumbs Up

Thank you Michael for your answer, I will check the leed interpretations immediately.

Id really appreciate if anyone can help me with the first question, is it necessary to have variable control of air in a VRF system if the fans motor horsepower are smaller than 5hp? Is that exception a valid path for submittal review purposes?

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Marcus Sheffer LEED Fellow, 7group Jan 27 2015 LEEDuser Expert 52887 Thumbs Up

1. Yes fans smaller than 5 HP do not have to meet this criteria.

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Gustav Alfaro Mechanical Engineer Jan 27 2015 LEEDuser Member 189 Thumbs Up

Thank you Marcus, that is good news

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Diego Pietzsch Mechanical Engineer
Jan 23 2015
Guest
29 Thumbs Up

Option 1: Zoning and controls

Project Location: Brazil

I've been working in a LEED CI: Retail for a small store in a mall.

I'm wondering to persue the option 1: zoning and controls for the project but i'm not sure if the sales floor of the store should be classed as a special occupancy that requires active controls for OA. Do you have any tips for that?

In case i have a single zone conditioned space that requires no active controls for OA. Would i still be eligible to earn these points?

Thank you

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Marcus Sheffer LEED Fellow, 7group Jan 23 2015 LEEDuser Expert 52887 Thumbs Up

I would need to check the Reference Guide to be sure but I think that the retail space would be a special occupancy. Since the space has highly variable levels of occupancy (like a conference room), it should have some controls beyond a thermostat. If you installed DCV on the single zone system it would probably qualify.

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Diego Pietzsch Mechanical Engineer Jan 27 2015 Guest 29 Thumbs Up

Thank you Marcus. It was very helpful.

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Gustav Alfaro Mechanical Engineer
Jan 07 2015
LEEDuser Member
189 Thumbs Up

Option 2 -question regargind baseline/budget building-

Hi to all:

On regards Option 2, the Reference Guide is clear about the thresholds that must be achieved as HVAC systems annual cost savings, but it is not clear if those savings can be boosted by energy conservation measures as installing additional insulation, reducing LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space., reducing miscellaneous loads, etc.

We are working on a 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. where we didn't have any responsibility on the design of the envelope, but the Owner has allowed us to implement enhancements on the existing fenestration and roof insulation which will lead us to improve our HVAC energy savings.

According to the Reference Guide, it is recommended to model in the design case any reduction in the miscellaneous loads if the project is pursuing EAc1.4, which makes us think that the same logic applies to other load vectors as the mentioned above, but there is no statement that clearly indicates it.

Id appreciate your help; and if we can take credit of the envelope enhancements please confirm if the baseline should be either the original building envelope or the 90.1 envelope requirements.

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Jan 08 2015 LEEDuser Expert 52887 Thumbs Up

This credit only deals with HVAC energy savings. The other systems are held neutral in both models and the HVAC enhancements are isolated to determine the percent savings. So you do not get any credit for envelop, lighting, or process loads.

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Gustav Alfaro Mechanical Engineer Jan 08 2015 LEEDuser Member 189 Thumbs Up

Thanks Marcus, but why is it suggested in the Reference Guide to take credit of the EAc1 energy reductions for modeling purposes just only in the proposed design if both cases should be held neutral?

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Marcus Sheffer LEED Fellow, 7group Jan 08 2015 LEEDuser Expert 52887 Thumbs Up

Please be more specific with your Reference Guide citation if you want me to take a closer look.

To me it makes no sense to allow savings from other building systems for this credit which is about the HVAC systems. I am open to being shown my error so please be more specific about what you are seeing (page number, section, etc.) in the Reference Guide.

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Chilufya Lombe Sustainability Consultant Solid Green Consulting
Jan 07 2015
Guest
378 Thumbs Up

Breakdown of HVAC points

Project Location: South Africa

Hi, for the HVAC Equipment points (5), our project meets the requirements of sections 1.4 and 2.9 of the core performance guide but not 3.10 since the system is constant volume (as most VRF and inverter split unit types are). Does this mean we cannot score any points at all?

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Marcus Sheffer LEED Fellow, 7group Jan 07 2015 LEEDuser Expert 52887 Thumbs Up

Correct, you must meet all three criteria to earn any points.

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Chilufya Lombe Sustainability Consultant, Solid Green Consulting Jan 12 2015 Guest 378 Thumbs Up

Thanks Marcus. Our only hope for the full 10 points is via the modelling route then, although 30% HVAC saving is quite challenging.

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Muzammal Abbas Electrical Design Engineer Pakistan Green Building Council
Dec 01 2014
Guest
4 Thumbs Up

Energy modeling

Project Location: Pakistan

Dear Sir,
I want to know that is it mandatory to provide energy modeling for commercial interior project's for LEED submission,
Now my second question is that i am using a HAP 4.8 and eQUEST software for energy modeling but in these there is no option for LEED CI only LEED NC is avalable for base case so what we should do because aur project is LEED CI,

kindly Sir give us the solution of it for LEED CI and if you have a sample project of LEED CI with complete detail for LEED Submission then email
Thank's
muzammal.sidework@gmail.com

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Marcus Sheffer LEED Fellow, 7group Dec 01 2014 LEEDuser Expert 52887 Thumbs Up

An energy model is not required for CI projects. It may be needed depending upon the option chosen for this credit but it is not required.

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Harsharan Kaur
Nov 03 2014
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51 Thumbs Up

Prescriptive Approach

Hi,
We are working for a CI project where the developer has provided a centralized HVAC system. We are following a prescriptive path for the HVAC compliance under EA Cr 1.3. In the LEED form we need to mention the pumps and fan details which should have variable frequency drive under criteria 3.10.

I wanted to know if these details will be only limited to 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. or we need to also list down the pump details of the common centralized system.

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Nov 03 2014 LEEDuser Expert 52887 Thumbs Up

In general I believe that the only equipment covered is that within the tenant scope of work.

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Michael Smithing Director - Green Building Advisory, Colliers International Nov 03 2014 LEEDuser Member 2860 Thumbs Up

The 5 credits for zoning can be achieved based on the system installed within the tenant scope of works. The 5 points for system efficiency are awarded based on the Landlord base building system, even though it is beyond the "project boundary." 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. on this - check the database for the details.

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Matthew Catterall Cotera+Reed Architects
Oct 10 2014
LEEDuser Member
94 Thumbs Up

Active controls and thermal control

We have a project with both perimeter and interior offices. Every office has occupancy sensing devices that are connected to VAVs so that the HVAC system can adjust when the office is not occupied. Isn't this normally sufficient for active controls? To achieve this credit, are we also required to provide thermostatic control for each office as well? We are only able to put thermostats in approx. 50% of our offices.

These questions come up for us because of our preliminary design reviewer's comments. For this credit our reviewer has advised:
"1. Perimeter private offices require a separate thermal control for each space paired with an occupant sensing or CO2Carbon dioxide sensing device, which is used to set back the temperature setpoint or airflow to the space when the space is unoccupied. Provide documentation to demonstrate that all perimeter private offices have been provided with active controls that are capable of sensing space use and modulating the HVAC system in response to space demand, such as demand controlled ventilation or occupancy responsive HVAC controls. 2. Interior private offices require a separate thermal control for each space. Provide documentation confirming that a separate thermal control is installed for each interior private office."

So, I don't know if they just didn't see the occupancy sensors on the drawings OR if they are saying that we need to provide something beyond that... By 'thermal control' for the interior private offices are they likely referring to providing a thermostat in each office?

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Terry Schroeder Senior Project Engineer, Whitman, Requardt & Associates, LLP Oct 14 2014 Guest 54 Thumbs Up

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. 10263 has the description of control devices now required in each type of space: http://www.usgbc.org/leed-interpretations?keys=10263&=Search

Every private office, both perimeter and interior, will need its own temperature control in order to qualify for this credit. The only argument you might have is if your project was registered before LI 10263 was published, in which case make sure you also look at LI 10242 to make sure you comply with those requirements. (assuming you registered after it was published)

This credit has become very difficult to achieve due to all of the control requirements, but there aren't many other ways for a tenant fit-out to affect energy use of the base building HVAC systems.

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Ken Williams
Sep 09 2014
LEEDuser Member
14 Thumbs Up

EAc1.3 Option 2: Baseline vs Alternate Baseline

I am working on a small building that is pursuing LEED CI. The building is comprised of two tenant spaces, office and restaurant/dining. The office space (pursuing LEED CI) is completely finished and occupied while the restaurant/dining is unfinished shell space. The restaurant/dining area does include Base Building HVAC equipment, plumbing and lighting for permit.

I would like to model the building using the Option 2 Baseline method. However, since the restaurant/dining is unfinished I am unsure how to model this space for lighting. Can I assume ASHRAE 90.1 values per Section 11 or should I use the Base Building lighting power densities which only include emergency lightingEmergency lighting as defined by the Illuminating Engineering Society of North America is lighting designed to supply illumination essential to the safety of life and property in the event of failure of the normal supply.? Your feedback is welcome.

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Marcus Sheffer LEED Fellow, 7group Sep 10 2014 LEEDuser Expert 52887 Thumbs Up

You model it the same as the Baseline allowance.

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Ken Williams Sep 10 2014 LEEDuser Member 14 Thumbs Up

Marcus, thank you for your response. Now that I read my question, I'm not sure I was clear in which space I had the question. It is the restaurant/dining space that I was unsure of.

If I use Base Building (Core and Shell) lighting it will only include emergency lightingEmergency lighting as defined by the Illuminating Engineering Society of North America is lighting designed to supply illumination essential to the safety of life and property in the event of failure of the normal supply. as the space is not built out. The other option, which I used in the LEED submission is to use the "not to exceed" LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. value listed in the Tenant Lease Agreement.

Thanks again.

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Marcus Sheffer LEED Fellow, 7group Sep 10 2014 LEEDuser Expert 52887 Thumbs Up

Perhaps it was my answer which was not clear.

Baseline means according to Appendix G/Section 11.

If you have a lighting design or a not to exceed LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. in the lease agreement then you can use those values to claim savings. However, for this credit under Option 2 I think you are supposed to hold all of the non-HVAC modeling inputs neutral (i.e. the same) to determine the HVAC percentage only. The procedure is in the Reference Guide.

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Brian Salazar President, LEED AP BD+C Entegra Development & Investment, LLC
Jul 10 2014
LEEDuser Member
181 Thumbs Up

How to interpret "Huddle Rooms"?

Hello - We are in the process of certifying an interior fit-up which utilizes a number of small "huddle rooms" which are enclosed spaces roughly the size of a private office, but furnished with occasional/lounge furniture for informal discussion (rather than a more formal conference table/chair setup). ASHRAE, Core Performance, and Local Code do not provide an specifics on how to treat Huddle Rooms w/r/t EAc1.3 Option 1 Zoning and Controls. They have been treated, conditioned, and controlled as open spaces due to their size, and expected utilization/occupancy of 2-4 persons at a time for short periods of time. In other words, they often share zones or controls with nearby spaces.

Our LEED Reviewer has requested that each Huddle Room be classified as a conference room requiring individual controls per room.

Question: Is there a formal 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. or other document that outlines the exact treatment of Huddle Rooms as they pertain to EAc1.3 Option 1? Has any other project team successfully pursued this credit and NOT provided individual controls for rooms like these?

Thank you!

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Terry Schroeder Senior Project Engineer, Whitman, Requardt & Associates, LLP Jul 17 2014 Guest 54 Thumbs Up

While I don't have experience with any projects using Huddle Rooms, as an outsider looking in I don't think you will be able to get this without the individual control.

What you have created with the Huddle Room is an enclosed space with a different load profile from the open office outside. Like it or not, these rooms still behave much like a conference room thermally, in that it is a more densely occupied space than the surrounding open office. The fact that they are used sporadically only serves to strengthen the argument that they should be controlled separately from the surrounding area. The intent of the credit is to ensure as much energy savings as possible given the limited impact most CI projects can have on the central HVAC system. Thus the requirement to turn off as much as possible when it isn't in use.

I am not a LEED official, but this is how I would interpret the issue. You can always ask further questions of your reviewer, or try to get them on the phone to plead your case.

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Brian Salazar President, LEED AP BD+C, Entegra Development & Investment, LLC Jul 21 2014 LEEDuser Member 181 Thumbs Up

They are the same size as offices, so if they were reclassified as offices, could we still pursue the credit, all else being equal?

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Terry Schroeder Senior Project Engineer, Whitman, Requardt & Associates, LLP Jul 21 2014 Guest 54 Thumbs Up

They will still need separate thermal controls if they are renamed as offices. Check out 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. #10263 to see what constitutes active controls for different types of spaces: http://www.usgbc.org/leed-interpretations?keys=10263&=Search

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Brian Salazar President, LEED AP BD+C, Entegra Development & Investment, LLC Jul 26 2014 LEEDuser Member 181 Thumbs Up

Thanks Terry. This is one of the most cost prohibitive credits in the LEED Reference Guide.

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Terry Schroeder Senior Project Engineer Whitman, Requardt & Associates, LLP
Jun 23 2014
Guest
54 Thumbs Up

Conflicting Requirements in Interpretations re: Active Controls?

I am working on a multi-story office fitout for a single tenant, and we received a review comment on our submission regarding EAc1.3 asking us to "provide documentation that all conference rooms have been provided with demand control ventilation PLUS thermostat setback." The reviewer then refers to LI#10242 and LI#10263 for further guidance.

Looking at LI#10242, the Ruling states "...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 (emphasis added) regulate temperature set point based on occupancy..."

In the subsequent LI#10263, the Ruling gives specific guidance for densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person)., requiring "a separate thermal control for each space paired with a CO2 or occupant sensing device, which is used for demand control ventilation AND (emphasis added) to set back the temperature setpoint to the space when the space is unoccupied."

My question is, does the later LI override the former? That difference between OR and AND is a big one, as the newer LI is adding a third requirement for densely occupied spaces (separate thermal zones, CO2-based DCV, AND occupancy sensors to force temperature setback). We have successfully submitted other tenant fitouts under this same rating system using just individual zone temperature sensors and CO2 sensors driving DCV, so to get this comment on our review was a shock. (Just when you think you understand the requirements...)

I'm also not certain how to use a CO2 sensor as an occupancy sensing device, as alluded to in the LI#10263 text. I suppose we could set some limit on CO2, perhaps a little below our limit for returning the damper to thermal control from DCV control, that would initiate temperature setback. That seems a little cumbersome though. We do have occ. sensors for our lights, but unfortunately they do not have the spare contacts required for connection to the HVAC control system.

I'm also not sure I'm on board with temperature setback during "occupied" hours in conference rooms. If we allow the temperature to rise to 80 deg F because the conference room is unoccupied, the next group to come into the room is going to be uncomfortable and the system may not be able to bring the temperature down to occupied setpoint quickly enough. I see this control causing a lot of headaches for building maintenance.

Thanks in advance for your time and advice.

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Michael Smithing Director - Green Building Advisory, Colliers International Jun 24 2014 LEEDuser Member 2860 Thumbs Up

We have just had this credit denied in final review because we do not meet the requirements of LI#10263. A previous project (same tenant, same floor) was registered before LI#10263 but reviewed afterwards - the review comments at that time specifically said that we did not need to incorporate the LI#10263 requirements but would have to for future projects.

My question relates to the requirement for DCV control in our project which has a CAV system. Our occupancy sensors turn off the fan-coil in the room when it is unoccupied which - we believe - results in the maximum energy savings possible. Is there a reason how DCV would contribute to the credit intent of increasing energy conservation in a CAV system? Cutting off fresh air to the conference rooms when unoccupied would simply redirect the air to other spaces without reducing power consumption. Indeed, an (admittedly very, very small) amount of additional energy would be required to modulate the dampers. Should we appeal this?

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Charles Nepps
May 22 2014
LEEDuser Member
484 Thumbs Up

Energy Modeling

We received a review comment back, on Energy Modeling report use to document EA cr1.3, that stated the following: "The Proposed design air cooled chiller COP for office is indicated 2.5 does not comply with the requirements of ASHRAE 90.1-2007, Section 6.4.1.1 which requires the minimum efficiency requirement of air cooled chiller per Table 6.8.1.C. This will preclude the project from using Alternate Baseline method"
The reviewer goes on to recommend using the Baseline method of modeling instead. My question is if the design chiller COP used in the model was too low to meet the requirements, couldn't we just simply rerun the model using the min. efficiency COP from Table 6.8.1.C. ...which should generated even better savings? Am I missing something here?

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Jatuwat Varodompun Dr, Green Building Soultion May 22 2014 LEEDuser Member 1659 Thumbs Up

Chiller efficiency is "mandatory" provision (6.4) which specify the minimum for each cooling epuipment. Failing to comply will lead to not meet requirement of credit EAp2 which is a prerequisite.

I am not sure with or have heard of the "alternate baseline method". Also waiting to see other comments.

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Charles Nepps May 22 2014 LEEDuser Member 484 Thumbs Up

Sorry, I believe to reviewer meant to say "Alternative" Baseline Method

The project can demonstrate the installed equipment meets the mandatory requirements, I believe the low COP value of 2.5 was entered in error during the modeling. It just concerns me that the reviewer's solution was to change to the "Baseline Method", rather than correct the input data for the model. Is it a case of once you've submitted a design chiller COP, are you stuck with it; so changing the existing model is not an option? Or is it because since the project is just a portion of an existing building, the Baseline Method is more applicable?

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Jatuwat Varodompun Dr, Green Building Soultion May 22 2014 LEEDuser Member 1659 Thumbs Up

You can change the model and simulate again. Simply write the narrative to explain the reviewer about the input mistake. However, please make sure the matching COP with the comissioning data EAp1 and EAc3.

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Charles Nepps May 23 2014 LEEDuser Member 484 Thumbs Up

Thanks for your help Jatuwat!
I've found some of the USGBC review comments confusing and I'm not entirely sure they will accept us simply changing the COP number. One of their comments seemed to question if the model was consistent with ASHRAE 90.1.2007 requirements at all.
Unfortunately I do not have a lot of experience with energy modeling; can you recommend any resources that would help me understand them better?

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Marcus Sheffer LEED Fellow, 7group May 23 2014 LEEDuser Expert 52887 Thumbs Up

Download the Advance Energy Modeling Guide for LEED from the USGBC web site.

If you are concerned about changing the COP provide additional documentation (product literature perhaps) to verify the correct COP.

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Ramana Koti Building Performance Analyst Lord, Aeck & Sargent
May 21 2014
Guest
181 Thumbs Up

trying to understand the effort

Hello. We're trying to decide if pursuing energy modeling under Option 2's Path 1 would be worth the effort. The project is a tenant fit out of the 23rd and 24th floor in one of the two 24 floor attached buildings the central plant serves. The HVAC design adds a few terminal units and one split system to serve a server room in the project scope but no major changes are made to the central plant. I understand that the entire two building complex and the central plant would have to be modeled in both the Baseline and Proposed Cases. The local HVAC modifications' efficiencies are only slightly better than ASHRAE 90.1 prescriptive values. The design does not meet the Option 1 requirements.

Given this, is there a way to estimate if 15% HVAC energy cost improvement is demonstrable or not before the data collection and modeling effort is taken up? It seems like a tall order especially if only two floors of the 48 or so floors are undergoing modest improvements.

Thanks for your attention.

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Chilufya Lombe Sustainability Consultant Solid Green Consulting
May 16 2014
Guest
378 Thumbs Up

Data centre and office

Hi, we have 2 buildings on our site pursuing two separate certifications. One is an office building and the other a data centre (one client). A portion of the office has some of the data centre equipment (command room) and is fed off a central system that serves the main data centre. Electricity for that room is also off the main data centre distribution board. Is it possible to model the energy use of the data centre portion of the office block with the main data centre and exclude it from the office model? (Even though it is housed in the office block)

The reason for doing this would be to simplify the model so that we don't have to try and apportion energy use from different parts of the data centre.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jul 25 2014 LEEDuser Moderator

Chilufya, I'm sorry for the slow response—have you figured out a solution to this?

My take would be that this would be very tricky in terms of managing these two projects as separate LEED certifications with overlapping energy models. The onus would be on you to show that you can do this is a way that is robust and makes real sense in terms of LEED.

Would it make any sense to put the data  center portion of the office building in the LEED boundary for the data center?

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Chilufya Lombe Sustainability Consultant, Solid Green Consulting Jul 29 2014 Guest 378 Thumbs Up

Hi Tristan, thanks for your response. I will suggest that and see how it affects the rest of the credits being targeted.

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Patrick Salmon EIT, LEED AP BD+C Highland Associates
May 01 2014
Guest
86 Thumbs Up

Appropriate Zoning and Controls Questions

We have an open office 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. project that is only pursuing the "Appropriate Zoning and Controls" portion of Option 1. I just had a few questions regarding how different space types are handled:

Copy Rooms (> 85 sqft): Do these rooms need their own active control? Are they compliant if the active controls and VAV box are intended for an adjacent conference room, but the copy room simply has a supply diffuser?

Storage Rooms: Similarly, is it sufficient that these rooms simply have a supply diffuser that provides air based upon the active controls in an adjacent private office? Do they need to be zoned separately?

Quiet Zones: We are planning on active controls in these spaces, which serve as a larger "enclosed" office for upwards of eight people. Are active controls necessary here?

Thanks for the help!
Patrick

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Marcus Sheffer LEED Fellow, 7group May 13 2014 LEEDuser Expert 52887 Thumbs Up

I do not think that a very small copy room or storage necessarily needs separate controls. Not sure about the quiet zones, sounds like they probably do.

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Steve Gross Interface Engineering
Mar 27 2014
LEEDuser Member
82 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 Member 1344 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.

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MM K
Mar 14 2014
Guest
1805 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 52887 Thumbs Up

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

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MM K Mar 14 2014 Guest 1805 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 52887 Thumbs Up

Which version of the form?

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MM K Mar 14 2014 Guest 1805 Thumbs Up

Version4

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Marcus Sheffer LEED Fellow, 7group Mar 14 2014 LEEDuser Expert 52887 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 1805 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 52887 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 1805 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 52887 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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Thiago Bondini
Mar 11 2014
LEEDuser Member
330 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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