EAc1: Optimize Energy Performance is, by far, the most important credit in LEED, based on the number of points available. Up to 19 points are at stake here based on how much you’re able to reduce the project’s predicted energy cost. That large amount of points also reflects the great importance LEED places on reducing energy use and forestalling climate change1. Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). (U.S. Environmental Protection Agency, 2008)
2.The increase in global average temperatures being caused by a buildup of CO2 and other greenhouse gases in the atmosphere. This temperature change is leading to changes in circulation patterns in the air and in the oceans, which are affecting climates differently in different places. Among the predicted effects are a significant cooling in Western Europe due to changes in the jet stream, and rising sea levels due to the melting of polar ice and glaciers..
You have some options to choose from. For certain buildings types you can opt to skip the energy modeling option and simply follow a list of prescriptive requirements, but you can’t earn nearly as many points that way, and you won’t have the benefit of the energy simulation to guide you to the most cost-effective energy efficiency measures.
This credit is documented in concert with EAp2: Minimum Energy Performance. Refer to EAp2 for detailed steps on LEED compliance and documentation.
An energy-efficient building can cost more to build, through components like efficient mechanical equipment and high-performance glazing. On the other hand, those same higher-cost measures can generate savings by reducing the size of mechanical systems. And of course, dramatic financial savings can come during the operational phase. Energy modeling can help determine the “sweet spot” for your project.
Your project may also qualify for financial incentives offered by utilities or local, state, and federal authorities, that help offset the premiums of system upgrades and renewable energy implementation. In many states, utilities or other local entities provide financial incentives in the form of rebates or tax breaks to alleviate the cost premiums associated with installing systems and purchasing equipment geared toward energy efficiency. (See Resources for incentives.)
Documentation for this credit happens along with documentation for the associated prerequisite, EAp2: Minimum Energy Performance. In fact, for the prescriptive options, all you have to do is document the prerequisite—no further information is required to earn a point under the credit.
Three compliance options are available.
With clearly defined goals and committed team members, your project should be able to achieve an energy cost reduction of 10% to 15%, through measures such as the following.
If you want to aim for higher targets of 20%–50% energy savings or higher, consider measures such as the following.
The most cost-effective measures vary by building type and location—refer to ASHRAE Advanced Energy Design Guides and case studies for appropriate strategies in your building. (See Resources.)
Building energy performance is a result of interactions between various different building components and systems. The mechanical system consumes energy based on factors such as architectural design, operating schedules, programming and climate. To significantly reduce energy it is very important for all team members to share design ideas and collaborate on strategies. The integrated design process will support constant communication, fast response on new ideas, and can help eliminate misunderstandings or assumptions—consider using it as a central strategy to earning points for this credit.
If your project is connected to a district energy system, LEED 2009 lets you take advantage of improved system efficiencies. Although not permitted for use with EAp2, you may include the improved efficiency over baseline of the district energy system in the energy model you develop for EAc1. In this scenario, you develop a separate model from the one for EAp2 compliance. (See Resources for more details through the updated guidelines.)
This credit is documented in concert with EAp2: Minimum Energy Performance. Refer to EAp2 for detailed steps on LEED compliance and documentation.
Begin identifying a target for energy performance. Begin by researching similar building types using the EPA Target Finder program. An Energy Star score of 80 or higher will typically earn EAc1 points.
To earn points for EAc1 you’ll most likely have to significantly exceed your local energy code. Achieving this energy reduction requires special attention to detail by your entire team from the beginning of the design process, and dedicated leadership from the owner.
Note that energy efficiency is not just about efficient boilers and chillers. To achieve high targets, the design of the building has to help reduce dependence on mechanical heating and cooling throughout the year, through measures like orientation, moderate glazing areas, and self-shading.
An automated building management system (BMS) can significantly reduce building energy use by turning down air conditioning and turning off lights during unoccupied hours, along with other similar measures. Occupancy sensors, timers, and temperature sensors feed into the system to switch off lights and fans when not needed. Note that controls can be counted towards energy reductions only through energy modeling.
The compliance paths for this credit are the same as for EAp2. Because the documentation is identical, it makes the most sense to consider credit implications when selecting the appropriate compliance path for the prerequisite.
Complying with Option 2 earns only one point, and with Option 3, 1-3 three points. If you are committed to greatly reducing energy usage and earning a higher number of points, then follow Option 1 for both EAp2 and EAc1.
Renewable energy shows the contrast between Options 1 and 3. Installing a renewable energy system for 5% of electricity use earns one-third of a point through Option 3. Installing a renewable energy system to reduce building energy costs by 2% earns one point under Option 1.
You can earn up to 19 points through EAc1, Option 1, using the same methodology as for EAp2, Option 1.
Only one point is available through Option 2: Prescriptive Compliance Path: ASHRAE Advanced Energy Design Guide, but if you choose this path for EAp2, it is earned automatically and does not carry any additional requirements. This option is available to office or retail projects up to 20,000 ft2 or warehouses less than 50,000 ft2. If you choose this compliance path, become familiar with the list of prescriptive requirements, and commit to meeting them. (See the AEDG checklist in the Documentation Toolkit.)
Up to three LEED points are available under Option 3 for compliance with the Core Performance Guide. It’s a good option if your project is smaller than 100,000 ft2, does not fall into one of the Option 2 categories and you’d rather not commit to energy modeling (Option 1). Your project automatically earns one point for meeting the prerequisite. An additional one or two points are available for meeting any three or six requirements, respectively, of Section 3. These requirements range from installing a renewable energy system to adding filters to air-handling systems. Review these requirements with your team to select the three or six that are most applicable to your project.
Some energy conservation measures, such as energy recovery ventilation or a highly insulated building envelope, add to both construction and design costs, though with an integrated design process these costs might be recouped through savings elsewhere, such as through reducing the size of the mechanical system. The most effective approach is to have your building owner and design team together evaluate both the first costs of the energy-saving measures and their effectiveness at reducing operating costs.
If you are connected to a district energy system, you are better off pursuing Option 1, because only through energy modeling can you benefit from the efficiencies of the district energy system.
The model you need to develop for EAc1 is the same as for EAp2 (unless you’re on a district energy system).
Follow the guidelines on identifying energy-efficiency strategies to achieve the owner’s energy efficiency goals per the Owner’s Project Requirements, developed for EAp1: Fundamental Commissioning.
Your mechanical engineer and energy modeler need to work in collaboration with the architect when finalizing building form, façade treatment, and programming—to give real-time input on the energy impact of all the design features.
Consider highly efficient systems like heat pumps for heating and cooling, district energy and cogeneration, ice storage for off-peak cooling, or energy recovery ventilation—to attain a substantial energy reduction of 10%-20%.
If your building includes the use of purchased steam supplied to your HVAC system, the proposed (design) building is modeled as if the steam system is “located” in the building— with the same efficiency with which it typically operates. The designed building is allocated only the fuel cost (for natural gas or oil) required to generate and deliver the steam needed for the building. The steam purchased is actually considered “free,” as steam rates are not included. And here is where your building really benefits—if the steam system also co-generates electricity along with steam, that electricity is assumed to be “free” to the proposed building, as well. (Refer to the latest guidelines from USGBC.)
Energy-efficient design can increase your construction budget. Use your computer model to optimize packages of upgrades that balance any added costs against cost savings, and run payback analyses to identify the most cost-effective options.
Even if you’re using Option 1, refer to the Advanced Energy Design Guides and Core Performance Guide (referenced by Options 2 and 3) for ideas on cost-effective measures to implement.
If you complete the documentation for EAp2, Option 2, you automatically earn a point through EAc1. The requirements are identical to EAp2 and require minimum additional time on the part of your engineer.
If you meet the prerequisite through Option 2, and document it, you earn a point through the credit—it’s that simple.
If you complete the documentation for EAp2, Option 3, you earn one point through EAc1, Option 3. The requirements are identical with EAp2 and requires minimal additional time on the part of your engineer.
Review Section 3 of the Core Performance Guide to identify three or six of the 11 available strategies (for one or two points, respectively) to pursue.
If you are installing a renewable energy system that provides at least 5% of your electricity, you already implemented one of the three strategies from the Core Performance Guide.
If you meet the prerequisite, and document it, you achieve one point —it’s that simple.
Note that the credit language excludes three of the strategies of the Core Performance Guide from helping you earn the credit. This is because these areas are covered thoroughly by other LEED credits.
Select those strategies that are most suitable for your project type and location. For example, evaporative cooling is very effective in a hot, dry climate but is not likely to be a good idea in the cooler, damper Northeast or Northwest. The list is a good summary of the best ways to reduce energy intensity, though some strategies may be more effective in offices and museums, while others are more helpful in hospitals and hotels.
Develop multiple iterations of your project design to analyze the energy impact of each change.
Further develop energy optimization strategies with the design team. Look at reducing loads while creating a comfortable environment within the shell. Look at reducing east and west exposures, and at providing south windows with exterior shades to make a design feature out of passive techniques. Discuss highly efficient system design at this stage, before your design is finalized—for example:
Ecotect and IES Virtual Environments, among other software tools, allow very quick analysis of alternative building forms and mechanical systems, allowing you to test alternative ideas, and develop a single idea in an iterative design process. (See Resources.)
Google SketchUp is good for shading studies, and plug-ins are available for IES and EnergyPlus to support energy analysis of Google SketchUp models.
Ventilation is one of the largest energy end-uses. Look at alternative means of ventilating your building. Consider naturally ventilated spaces, mixed-mode ventilation for moderate climates, and demand-controlled ventilation for mechanically ventilated spaces.
Daylighting makes for welcoming spaces, and can save energy both through reduced electric lighting and reduced cooling load due to the reduced electric lighting. Consider an atrium and skylights to serve ventilation and light functions. Integrate spatial programming within the atrium to utilize the space. See LEEDuser’s daylighting strategy for more.
Consider other techniques to upgrade the building envelope and insulation, such as:
By this stage, the architect should have seen a visual presentation by the energy modeler on multiple building forms with energy-use comparisons. This will help hone in on the most energy-efficient design that also supports the building program.
Follow EAp2 steps for compliance and documentation.
If you are pursuing an additional point or two by complying with Section 3, select the strategies you anticipate pursuing.
Some easily implemented strategies include:
One complete run of your energy model should be completed during design development to make sure the design is reducing annual energy cost by your targeted amount. This is the time when simplified models used to inform early design decisions should be replaced by a more comprehensive detailed model. Run two or three alternatives to help the designers finalize envelope and system selection. Common measures to consider include high-performance windows, additional roof insulation, and more efficient boilers.
Use your energy model to review envelope thermal and hygrothermal performance. In a heating climate, thick insulation inside the air barrier may cause condensation problems. Consider an exterior thermal barrier to protect the air barrier and to prevent condensation inside the wall cavity. Identify thermal bridges in the walls and windows that could leak heat from inside. Add thermal breaks, such as neoprene gaskets, on shelf angles, silicone beading on window frames, and use other techniques to prevent leakage from the envelope.
Your energy model can be a supportive design tool that provides insight into the actual performance of the building envelope and mechanical systems. It can highlight surprising results, such as a prominent feature like an efficient boiler contributing only a 1% reduction in energy cost. It can also provide evidence to support operational energy-use decisions such as changing the heating or cooling set points a few degrees.
The baseline exterior lighting power allowance (ELPA) may not take credit for any category which does not have any lighting fixtures in the proposed building, or for any area or width within any category which is not lit in the proposed building, even within the tradable categories. In addition, the lighting for a single building component cannot be counted within two separate categories in the baseline ELPA calculations.
Make sure the identified measures are being implemented. For Section 3 items, check with the mechanical engineer on the status of each measure. Document the measures if they are completed, like daylight control locations and quantities and economizer performance.
Finalize the design, including all energy system strategies. Make sure your project is on track for the target rating based on energy cost.
Assess your compliance with the credit and projected points to be earned. This credit and option can be the largest contributor to your LEED point total, so if you aren’t hitting your goal, consider last minute design changes now.
Specify and contract for efficiency measures. Often new equipment and novel systems are unknown to contractors, so hold bid and construction meetings to ensure your specifications are understood and everything is purchased and installed as intended.
The more thorough your drawings and specifications are, the less the chances of incorrect installation.
Contracting with a commissioning agent for the expanded scope of EAc3: Enhanced Commissioning is highly recommended. Any project relying on sophisticated controls and systems for energy efficiency needs the eye of an experienced commissioning agent during construction and functional testing.
Energy systems are only as efficient as they are well-installed and operated—involve the operations team during the final Construction Documents phase (or even much earlier) to make sure they are abreast of design decisions and prepared to operate in the sequence required.
Make sure mechanical spaces and locations are coordinated in the architectural and structural drawings. For example, is a duct run colliding with a beam? Is a fan coil unit placed above a door opening so that it will leak condensate on people walking into the space? Common mistakes like this can cause construction delays and poor performance during operations if not detected, so coordination of the drawings is critical, especially if your project involves integrated design and complex systems.
When your final design is documented, run a final energy model for LEED documentation. Include the specifications and efficiencies of the system being purchased and installed.
Finalize the list of strategies adopted from Section 3. Your project earns one point for three strategies, two points for six strategies.
All the design work is implemented during construction. Have the project architect ensure that the glazing is per your specifications and that the façade system incorporates a continuous air barrier. The commissioning agent will ensure all equipment purchased is exactly what the engineer required, and that all pumps and fans meet the specifications.
If you are installing a BMS, configure and program it to specifications. If there was any change in system specifications, make sure it is accounted for in the BMS programming.
If you are installing sensors and controls, they should be configured per specifications. Surprisingly, these are occasionally mis-calibrated or even reversed, causing discomfort to occupants, cost to the owner, and system malfunction.
Although EAc1 is a Design Phase submittal, it may make sense to submit the credit after construction for LEED certification to take into account any final design changes.
Make sure that the documentation from the prerequisite (EAp2) is complete in LEED Online. The documentation for EAc1 is, for the most part, automatically filled out in LEED Online based on your entries for EAp2.
Install all equipment as required by the design specifications.
If your team is installing features like VAV or a peak-load demand response system for the first time, check the installation and functional testing carefully. Get the vendor involved in writing the specifications to reduce risk of errors.
The first year of operations is usually a learning period for both the occupants and the facility manager. If your project underwent enhanced commissioning and developed an operations manual, you will have fewer miscommunications and untrained staff. Most medium and large projects install a BMS that centrally controls fans, pumps, part of the chiller and boiler load, and provides real-time energy-use data. Note that certain configurations require resetting, per feedback from users and the system itself.
Excerpted from LEED 2009 for New Construction and Major Renovations
To achieve increasing levels of energy performance beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use.
Select 1 of the 3 compliance path options described below. Project teams documenting achievement using any of the 3 options are assumed to be in compliance with EA Prerequisite 2: Minimum Energy Performance.
Demonstrate a percentage improvement in the proposed building performance rating compared with the baseline building performanceBaseline building performance is the annual energy cost for a building design, used as a baseline for comparison with above-standard design. rating. Calculate the baseline building performance according to Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) using a computer simulation model for the whole building project. Projects outside the U.S. may use a USGBC approved equivalent standard2. The minimum energy cost savings percentage for each point threshold is as follows:
Appendix G of Standard 90.1-2007 requires that the energy analysis done for the building performance rating method include all the energy costs associated with the building project. To achieve points under this credit, the proposed design must meet the following criteria:
For the purpose of this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators, kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g., lighting integral to medical equipment) and other (e.g., waterfall pumps).
Regulated (non-process) energy includes lighting (e.g., for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilating, and air conditioning (HVAC) (e.g., for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes.
For this credit, process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard 90.1-2007 G2.5) or USGBC approved equivalent to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and proposed design, and theoretical or empirical information supporting these assumptions.
Projects in California may use Title 24-2005, Part 6 in place of ANSI/ASHRAE/IESNA Standard 90.1-2007 for Option 1.
Comply with the prescriptive measures of the ASHRAE Advanced Energy Design Guide appropriate to the project scope, outlined below. Project teams must comply with all applicable criteria as established in the Advanced Energy Design Guide for the climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. in which the building is located. Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
The building must meet the following requirements:
Comply with the prescriptive measures identified in the Advanced Buildings™ Core Performance™ Guide developed by the New Buildings Institute. The building must meet the following requirements:
Points achieved under Option 3 (1 point):
Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
1Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1-2007 if it is approved by USGBC as an equivalent standard using the process identified in the LEED 2009 Green Building Design and Construction Global ACP Reference Guide Supplement.
Design the building envelope and systems to maximize energy performance. Use a computer simulation model to assess the energy performance and identify the most cost-effective energy efficiency measures. Quantify energy performance compared with a baseline building.
If local code has demonstrated quantitative and textual equivalence following, at a minimum, the U.S. Department of Energy (DOE) standard process for commercial energy code determination, the results of that analysis may be used to correlate local code performance with ANSI/ASHRAE/IESNA Standard 90.1-2007. Details on the DOE process for commercial energy code determination can be found at http://www.energycodes.gov/implement/determinations_com.stm.
1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1‐2007 if it is approved by USGBC as an equivalentstandard using the process located at www.usgbc.org/leedisglobal.
This database shows state-by-state incentives for energy efficiency, renewable energy, and other green building measures. Included in this database are incentives on demand control ventilation, ERVs, and HRVs.
ASHRAE offers guidance for different levels of building energy audits.
ACEEE is a nonprofit organization dedicated to advancing energy efficiency through technical and policy assessments; advising policymakers and program managers; collaborating with businesses, public interest groups, and other organizations; and providing education and outreach through conferences, workshops, and publications.
ASHRAE has developed a number of publications on energy use in existing buildings, including Standard 100–1995, Energy Conservation in Existing Buildings. This standard defines methods for energy surveys, provides guidance for operation and maintenance, and describes building and equipment modifications that result in energy conservation. 2 publications referenced by this credit (ANSI/ASHRAE/IESNA 90.1–2007 and ASHRAE Advanced Energy Design Guide for Small Office Buildings 2004) are available through ASHRAE.
Energy Star is a joint program of U.S. EPA and the U.S. Department of Energy that promotes energy-efficient buildings, products, and practices.
The Solar Heating and Cooling Programme was established in 1977, one of the first programmes of the International Energy Agency. The Programme's work is unique in that it is accomplished through the international collaborative effort of experts from Member countries and the European Commission.
The New Buildings Institute is a nonprofit, public-benefits corporation dedicated to making buildings better for people and the environment. Its mission is to promote energy efficiency in buildings through technology research, guidelines, and codes.
The Building Energy Codes program provides comprehensive resources for states and code users, including news, compliance software, code comparisons, and the Status of State Energy Codes database. The database includes state energy contacts, code status, code history, DOE grants awarded, and construction data. The program is also updating the COMcheck-EZ compliance tool to include ANSI/ASHRAE/IESNA 90.1–2007. This compliance tool includes the prescriptive path and trade-off compliance methods. The software generates appropriate compliance forms as well.
This extensive website for energy efficiency is linked to a number of DOE-funded sites that address buildings and energy. Of particular interest is the tools directory, which includes the Commercial Buildings Energy Consumption Tool for estimating end-use consumption in commercial buildings. The tool allows the user to define a set of buildings by principal activity, size, vintage, region, climate zone, and fuels (main heat, secondary heat, cooling and water heating) and to view the resulting energy consumption and expenditure estimates in tabular form.
Non-profit organization aiming at design community to increase collaboration for designing energy efficient buildings.
International association of energy modelers with various national and local chapters.
The Low Impact Hydropower Institute is a non-profit organization and certification body that establishes criteria against which to judge the environmental impacts of hydropower projects in the United States.
The Building Technologies Program (BTP) provides resources for commercial and residential building components, energy modeling tools, building energy codes, and appliance standards including the Buildings Energy Data Book, High Performance Buildings Database and Software Tools Directory.
This online resource, supported by Natural Resources Canada, presents energy-efficient technologies, strategies for commercial buildings, and pertinent case studies.
This website provides details process to develop an energy model.
Research warehouse for strategies and case studies of energy efficiency in buildings.
An online window selection tool with performance characteristics.
DOE website with database of energy performance of buildings across US.
This website lays out design process for developing an energy efficient building.
This website is put together for architects with ideas on hundreds of ways to improve design for lower energy demand.
This document lists multiple web based or downloadable tools that can be used for energy analyses.
This webtool is a database of strategies and vendors for energy efficient systems.
Energy design tools are available to be used for free online or available to download.
This website lists performance characteristics for various envelope materials.
This is an online forum of discussion for energy efficiency, computer model software users.
This directory provides information on 406 building software tools for evaluating energy efficiency, renewable energy, and sustainability in buildings.
Weather data for more than 2100 locations are available in EnergyPlus weather format.
Weather data for U.S. and Non-U.S. locations in BIN format.
A web-based, free content project by IBPSA-USA to develop an online compendium of the domain of Building Energy Modeling (BEM). The intention is to delineate a cohesive body of knowledge for building energy modeling.
The Commercial Buildings Energy Consumption Survey (CBECSThe Commercial Buildings Energy Consumption Survey (CBECS) is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures. Commercial buildings include all buildings in which at least half of the floorspace is used for a purpose that is not residential, industrial, or agricultural, so they include building types that might not traditionally be considered "commercial," such as schools, correctional institutions, and buildings used for religious worship. CBECS data is used in LEED energy credits.) is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures.
ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry.
These guidelines are available as a free download or can be purchased as a printed manual of 390 pages.
This Standard Practice provides useful, practical guidance on the technical issues where current research and consensus opinion have advanced, including information on design elements that can produce both a productive and pleasant work environment.
This information is of particular benefit to building design practitioners, lighting engineers, product manufacturers, building owners, and property managers. Although the text emphasizes the performance of daylighting systems, it also includes a survey of architectural solutions, which addresses both conventional and innovative systems as well as their integration in building design.
EDR offers a valuable palette of energy design tools and resources that help make it easier for architects, engineers, lighting designers, and developers to design and build energy-efficient commercial and industrial buildings in California.
This ongoing project explores the effects of computers and other information technology on resource use.
The Handbook provides up-to-date coverage of lighting development, evaluation and interpretation of technical and research findings, and their application guidelines.
The Ninth Edition provides students and professionals with the most complete coverage of the theory and practice of environmental control system design currently available. Encompassing mechanical and electrical systems for buildings of all sizes, it provides design guidelines and detailed design procedures for each topic covered. It also includes information on the latest technologies, new and emerging design trends, and relevant codes and zoning restrictions-and its more than 1,500 superb illustrations, tables, and high-quality photographs provide a quick reference for both students and busy professionals.
This manual covers nearly all disciplines involved in the design, construction and operation of green buildings.
This website is a fast growing news portal for energy efficiency in buildings showcasing success stories, breakthrough technology or policy updates.
Bimonthly publication on case studies and new technologies for energy efficiency in commercial buildings.
This is a quarterly publication for the group of energy modeling.
This professional architects organization is a very good starting point for architects looking to start energy efficient design.
Fall 2008 guideline and performance goals developed by federal government.
Information about energy-efficient building practices available in EDR's Design Briefs, Design Guidelines, Case Studies, and Technology Overviews.
This manual is a strategic guide for planning and implementing energy-saving building upgrades. It provides general methods for reviewing and adjusting system control settings, plus procedures for testing and correcting calibration and operation of system components such as sensors, actuators, and controlled devices.
This weblink leads to NBI website to download the standard for free.
State of the art lighting research center at RPI provides all information terminologies of lighting design, strategies for efficient lighting and product reviews after experimental testing.
This document is USGBC’s second (v2.0) major release of guidance for district or campus thermal energy in LEED, and is a unified set of guidance comprising the following an update to the original Version 1.0 guidance released May 2008 for LEED v2.x and the initial release of formal guidance for LEED v2009.
This manual offers guidance to building energy modelers, ensuring technically rigorous and credible assessment of energy performance of commercial and multifamily residential buildings. It provides a streamlined process that can be used with various existing modeling software and systems, across a range of programs.
Chapter 19 is titled, “Energy Estimating and Modeling Methods”. The chapter discusses methods for estimating energy use for two purposes: modeling for building and HVAC system design and associated design optimization (forward modeling), and modeling energy use of existing buildings for establishing baselines and calculating retrofit savings (data-driven modeling).
Required reference document for DES systems in LEED energy credits.
ENERGY-10 is an award-winning software tool for designing low-energy buildings. ENERGY-10 integrates daylighting, passive solar heating, and low-energy cooling strategies with energy-efficient shell design and mechanical equipment. The program is applicable to commercial and residential buildings of 10,000 square feet or less.
This website includes information from the developers of DOE-2 and DOE-2 products, such as eQUEST, PowerDOE, and COMcheck-Plus.
This is the list of all software approved by DoE that can be used to run simulation for LEED purpose.
This is a tool available to download for envelope moisture analysis tool.
BIM is a popular design tool that allows collaboration among all team members and allows quick outputs of all analyses.
DesignBuilder is a Graphical User Interface to EnergyPlus. DesignBuilder is a complete 3-D graphical design modeling and energy use simulation program providing information on building energy consumption, CO2Carbon dioxide emissions, occupant comfort, daylighting effects, ASHRAE 90.1 and LEED compliance, and more.
IES VE Pro is an integrated computing environment encompassing a wide range of tasks in building design including model building, energy/carbon, solar, light, HVAC, climate, airflow, value/cost and egress.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-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 restrictsions for these forms; for more information, visit LEED Online and click "Sample Forms Download."
In your supporting documentation, include spec sheets of equipment described in the Option 1 energy model or Options 2–3 prescriptive paths.
Sometimes the energy simulation software being used to demonstrate compliance with Option 1 doesn't allow you to simulate key aspects of the design. In this situation you'll need to write a short sample narrative, as in these examples, describing the situation and how it was handled.
This is a sample building energy performance and cost summary using the Performance Rating Method (PRM). Electricity and natural gas use should be broken down by end uses including space heating, space cooling, lights, task lights, ventilation fans, pumps, and domestic hot water, at the least.
This spreadsheet lists all the requirements for meeting EAp2 – Option 3 and and EAc1 – Option 3. You can review the requirements, assign responsible parties and track status of each requirement through design and construction.
Option 1 calculates savings in annual energy cost, but utility prices may vary over the course of a year. This sample demonstrates how to document varying electricity tariffs.
This graph, for an office building design, shows how five overall strategies were implemented to realize energy savings of 30% below an ASHRAE baseline. (From modeling conducted by Synergy Engineering, PLLC.)
The climate zones shown on this Department of Energy map are relevant to all options for this credit.
This spreadsheet, provided here by 7group, can be used to calculate the fan volume and fan power for Appendix G models submitted for EAp2/EAc1. Tabs are included to cover both ASHRAE 90.1-2004 and 90.1-2007 Appendix G methodologies.
Documentation for this credit can be part of a Design Phase submittal.
I am working on a energy modeling for a relocation industry factory, The entire space is conditioned. Since the air clean condition of production area has a high requirement, the factory design 100% outdoor air to meet the requirement before. With the improvement of the production process, now the factory allow to design 30% outdoor air and 70% recycle air to meet the requirement. And now, I have two questions:
1. Can this kind of 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. system be looked as process system?
2. If can be looked as process system, the new design outdoor air flow rate is different with old design. How to model it in the baseline modeling?
1. Since the system also conditions the air for people it cannot be considered strictly process.
2. It should be modeled identical to the Proposed in the Baseline in actual airflow not percentage. If you are attempting to claim any energy savings relative to this strategy then you would need to submit it as an exceptional calculation.
We have an industrial plant where the process loads are assumed to be, say, 98% of all building energy use. Therefore, even if the non-process building portion was Net Zero Energy, we would not meet the minimum LEED-NC 2009 prerequisite of 10% energy reduction. However, the process equipment specified appears to be new and with exceptional energy performance over traditional equipment. The Question: Can we meet the prerequisite (and maybe get points) by demonstrating a 10% (or better) energy improvement primarily through process load savings? This would employ the Exceptional Calculation Method. Assume the rest of the building meets or exceeds ASHRAE 90.1-2007 and is modeled according to the rules. Thanks.
Yes you can!
Jeff, I had a similar issue with a heavy manufacturing plant project. I think the following 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. would be helpful for you. http://www.usgbc.org/leed-interpretations?keys=10291
I am working on a LEED project in Qatar and wanted to query USGBC on using aircooled chillers in the baseline building instead of water cooled chillers. Has anyone requested permission to change the baseline HVAC system for energy modelling and received a positive answer ?
I think that this question has been asked in the past and denied. I am not aware of any baseline system changes outside the standard being granted. Make sure to check the exceptions to G3.1.1 to see if any apply.
The guide allows to use a USGBC approved equivalent standard for projects outside the US. Where can this list of approved standards be found?
Go to the USGBC website and type in "Global ACP" in the search box. This document provides some standards for foreign projects, but I think you need to find it yourself and submit to USGBC for review. Better to do this as early in the project as possible as it takes USGBC time on these reviews.
I am not aware of a generated list otherwise. Be interesting to know if there has been one pulled together somewhere?
I am using option 1 a computer simulation model to carryout the calculations. I am trying to get the additional points for demonstrating the cost reduction in Process energy. The building in question has quite complex process energy with a lot of equipment, is there any boundary to what process equipment should be included or should every small pump and motor be included even if its only <0.5kW. There could be hundred of these small items which would need to be investigated to see how long they actually run for each day, week or the year! Any help would be appreciated.
All energy use within and associated with the project must be included in the models.
When modeling the process loads, you are allowed to use industry accepted values and schedules for the project type if you cannot determine the actual expected process load values. Two sources off the top of my head are COMNET and the 90.1 User's Manual. The other option is to account for each piece of process equipment and model it as accurately as you can. You could also determine a generic schedule for the process equipment and apply it instead of developing a schedule for each piece of equipment. So you have options relative to how you model the process.
Now if you are claiming energy savings relative to process you can't use the default values and schedules as the baseline. You will need to clearly state the baseline and defend it as reasonable. Some baselines for process are established like certain equipment within LEED for Retail. Beyond the established baselines reasonable is defined as the industry standard for that process within that building type in that geographic area.
When we do our modeling work we almost always inventory the expected equipment being installed and model that as accurately as we can including schedule modifications where applicable. The time to do so is factored into our fee proposal based on the expected process equipment likely in the job.
The basic issue here is how important is an accurate prediction to this particular project?
Thanks for your response.
I was wondering about what you meant when you say " including schedule modifications where applicable". Do you just mean making chafes to the information provided and inputing it into the model.
I am going to to get all the input power form the machinery and possibly any steam driven process plant too and add it to the model, to get the most accurate comparison as hopefully get the points we need.
"Beyond the established baselines reasonable is defined as the industry standard for that process within that building type in that geographic area." Where would I get this if the process machinery is very specialised, is this covered in 90.1?
Thanks for your help.
I meant using different schedules for different pieces of equipment.
That is the point it is not covered by 90.1. Establishing the appropriate baseline is the responsibility of the project team. With specialized process equipment you would likely get this information from the owner, the product manufacturer, an industry association, designer who specializes in specifying the equipment, or other research sources.
I am trying to model the use of two daylight controls in an industrial storage building with few windows and skylights with only 20% of transmittance. The daylighting is about 6,3% however when modelling the use of illuminance controls, the reduction of interior lighting is not coherent with daylighting results since it considers about 8 hours reduction of interior lighting. I think that these results are related to the way that the simulation software calculates the use of lighting controls, that does not consider the real transmittance of the glazing used. In this case, should I present the results obtained, but try to justify why they are not reliable? If so, how can I calculate the percentage of reduction of interior lighting?
Thank you in advance!
If the space is heated and/or cooled you will have to include the daylighting control within in modeling software to account for the interactive effects. If there is no heating or cooling then you could do the calculations outside the modeling software. Either way you would need to do an exceptional calculation.
What software are you using?
I am using Design Builder v3.4.0.039 (Energy Plus v8.1). We don't have any heating or cooling in the space. Can you advise any calculation method that we could use?
That software definitely accounts for the glazing visible light transmission. The calculation methodology used within EP would also be acceptable for LEED. I would not use something else, I would use EP. Perhaps there is an input error? You could contact the EP help desk for more specifics.
Any help regarding the reuse of an existing building LEED simulation would be helpful. We are working on an existing building that was a warehouse and is now an office building. The existing shell was un-insulated concrete block walls and an un-insulated metal roof with metal joists. Using the ASHRAE 90.1 guidelines for envelope allows the use of existing envelope, but in the climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. at-hand our proposed envelope alone represents a 30% energy cost savings. Our question is whether there is an exception or limitation to using existing the envelope if a building use is changed, ours is now an office.
In my opinion if your existing situation is an unconditioned space, using the existing envelope in the Baseline does not apply. I base this on the definition of the term building envelope which separates conditioned spaces from the exterior. Your Baseline envelope should be from the Table 5.5-X values.
I'm performing an energy model that is a renovation of an existing structure. The existing structure has a sheet metal roof, two vertical sheet metal walls, and 4" concrete slab. Two of the vertical surfaces are open.
Per Appendix G, can I model the existing envelope, a 90.1 Section 5 minimum envelope, or a combination of the two?
Sounds like the space was unconditioned in its existing situation. As such you would need to use the Section 5 minimum values for the baseline.
I am working in an Office block project (conditioned area- 8500 sqft). VRF systems have been considered for it. The modelling software that we are using is Visual DOE which unfortunately cannot model VRFs. The HVAC baseline for the project is System 4- PSZ HP (Appendix G, Table 3.1.1a). Is it acceptable if in the design case, I consider PSZ system but EER of 13? As VRF is far efficient than PSZ systems, even one with EER of 13 may not match VRF's efficiency. Please provide me suggestions. Thanks.
Since you will be using a work around you are required to explain it per G2.2. You would need to provide justification for any efficiency improvement you are claiming. Making sure that you model is conservative and demonstrating that is the case will improve your chances of getting the work around approved by the reviewer. See also 90.1-2010 which added VRF systems to the 6.8.1 tables.
I am working on a large building which is part theater, part convention center and part exhibitions halls + ancillary spaces. The baseline system is system type 7. App G says "For systems 5,6,7 and 8 each floor shall be modeled with a separate HVAC system". The building has many different levels and lots of spaces which span over multiple floors (Such as exhibition halls). The most common sense approach seems to be to match the baseline HVAC system zoning as per the proposed however this is not compliant with the sentence in App G (unless it is intended to imply a minimum of one HVAC system per floor). Is this correct?
If it is the case that each floor has to have 1 HVAC system in the baseline how do you determine the pressure drop adjustment for each floor? Each floor will be served by many different 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. types (e.g if some AHU's have heat recovery and others don't etc) and therefore there would be multiple values.
Correct you must model a system per floor.
Very hard to say exactly how to apply the pressure drop adjustments without seeing the situation but in general you apply the ones that are part of the proposed systems serving that floor. If a proposed system covers a portion of a floor and a pressure drop adjustment only applies to a part of a floor you would proportion the adjustment based on the supply air flows. In the case of heat recovery you only apply the baseline pressure drop adjustment for it if the baseline system is required to have heat recovery according to G220.127.116.11. Also if you apply any of the G3.1.1 exceptions you may need to model a second system on a particular floor.
Couple of other clarifications:
- If I have floors at different heights across the buildings (E.g half the building is at 3m and the other half at 3.6m) would you split based on floor number, e.g this would all be 2nd floor so 1 baseline HVAC system for the floor or floor height so this would be 2 baseline HVAC systems to cover the 2nd floor.
- For spaces which spans several floors (e.g theaters, exhibition halls) should they be on baseline HVAC system for the floor they start on?
Again hard to say without seeing the whole situation but if I had a floor that was at a slightly different level I would probably still count it as all one floor.
Yep the area is based on floor space.
The fenestration supplier of a project gave us SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. values from a simulation. We would like to know if it is acceptable for LEED simulation. The supplier states the following:
"Simulations ere run using LBNL Windows 7, Optics 6 and WIS software with version 29.0 of the International Glazing Database."
That should be acceptable. Make sure that your modeling methodology is consistent with the Window 7 calculations. So if Window 7 calculated the overall assembly SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. when you model the windows you would not model the frames separately since the Window 7 calculation determines an overall assembly value. As usual be sure to explain how the windows were modeled in your LEED documentation to avoid a very common review question.
As baseline model I have to model System 6 according to Table G3.1.1A. On a floor the spaces that have windows are naturally ventilated while the internal spaces are mechanically ventilated. G3.1.1 states that "For system 5, 6, 7, and 8 each floor shall be modeled with a separate HVAC system". I think that modeling only one 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. for the whole floor would be inappropriate, because in the baseline model outdoor air would be provided through the mechanical system to the whole floor (while in the proposed model only some spaces are mechanically ventilated). For this reason in that floor I would model two AHUs: one doesn't supply outdoor air and is connected only with spaces that are naturally ventilated. Would it an acceptable solution?
Another issue: 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. that supplies air in the proposed model has an extraction fan. In the baseline model I would model one AHU with the extract fan (the AHU that supplies also outdoor air) and one AHU without extract fan.
Do any of the G3.1.1 exceptions apply?
In the zones that have openable windows there are offices, while the central zones are: one conference room, one restroom, one corridor. Because of the presence of people and electronic devices in the conference room I estimate an internal thermal load equal to 50 W/m^2, i.e. > 31.2 W/m^2 (exception b). Could I model a separate system only for the conference room?
You are required to do so if the conference room meets the exception b criteria.
To your original question - You would still create one system per floor. You cannot create a separate system. Supply the quantity of outdoor air in the baseline identical to the outdoor air supplied in the proposed.
Our office building is placed in Copenhagen, Denmark.
Our question is which climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. to use? Is it zone 5, zone 6 or can we use either one of those?
- We are using a simulation Tool (IES-VE) which automatically suggests zone 6 as soon as Copenhagen is picked as location.
- However, according to the ASHRAE Standard 90.1-2007 table B-4 for international climate zone definitions we land in zone 5 with a HDD65F of 6288 hours.
No you don't get to pick one. If you are using the 90.1 baseline then you need to use the climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. assignment from 90.1. It sounds like IES-VE is in error assuming your 6288 is correct. You might want to ask them why it is showing up in their software as a zone 6. Perhaps they have different HDD65F data?
For a project located in the baltic area, we used the BSR/ASHRAE Addendum b to ANSI/ASHRAE Standard 169-2006 where there are maps of europe and the other continents and their climate zones. According to these maps, Copenhagen has climate zone 5A - cool humid.
I have a LEED 2009 project where all buildings are pursuing LEED certification and are served by the same plant (for heating and cooling). All buildings served by the plant are included in the LEED scope. The district guide states: "The central plant is defined as a DES only if it currently serves or is expected to serve other buildings not within the LEED project boundaries for the project."
Does this mean the district energy guide does not apply to my project? If so how do I address the reference buildings?
Have you checked the campus application guide?
Here is the link - http://www.usgbc.org/sites/default/files/Docs10486.pdf
It references Appendix A which provides modeling guidelines for your situation -http://www.usgbc.org/Docs/Archive/General/Docs10484.pdf
Not sure why the link above is cut off. The last two letters are df - so copy and paste to get to that link.
I discovered this guide shortly after posting. I had looked at the District Energy Guide, Advanced Energy Modeling Guide for LEED as well as the Reference Guide of course. You only have to go through 4 different manuals to find the answer...simple.
For v4 most of this will be consolidated into the Reference Guide subscription if you choose to go that route. Hopefully getting simpler.
Hello everyone, we are working on a laboratory and we have very restrictive filtering in some spaces there are equipments that have MERVMinimum efficiency reporting value. 7 + MERV 13 + MERV16 filtering sections.
In the ASHRAE preassure adjustment calculations we have that for MERV 7 we have a adjusment of 0.5 in.w.c.
MERV 13 is 0.9 in.w.c.
MERV 16 is calculated 2x the clean filter which is 1.8 x 2=3.6.
¿How do we calculate the adjustment ?
0.5+0.9+3.6=5 or (0.5+0.9+1.8)x2=6.4
If the MERVMinimum efficiency reporting value. 16 pressure drop is indeed 1.8 then you would use 3.6. Your first equation is the correct one.
We are working on a factory in Chicago which will have food producing greenhouses on the roof. We are pursuing LEED Platinum and are wondering how to prevent being penalized for energy use by the greenhouses. Someone mentioned that the USGBC provided some special allowance or designation for the greenhouses.
Does anyone know about this?
The energy used by the green house would likely be a process load and modeled identically in both cases.
Our project will have a biofuel system that utilizes agricultural crops as the biofuel. Per the LEED reference guide this is considered to be renewable energy. If the crops are grown offsite I do not believe the energy production can be subtracted from the proposed model since ASHRAE 90.1, Appendix G and the LEED reference guide specifically require the energy to be either "on-site" or "site recovered".
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. #10020 made on 5/9/11 seems to confirm this.
Could an exeptional calculation method be performed such that the project receives the benefit under EAc1 for the biofuel system?
No an exceptional calculation would not apply. There is some precedence for claiming off-site renewables, like landfill gas. You would need to make a strong case relative to the future availability of the fuel supply. It would probably be hard to do so but maybe not impossible.
We were not involved in documenting the credit, but we have a university client that makes significant energy and heating steam using biomass, a waste stream from a local large food producer. This was accepted as renewable energy under EAc2 (v2.2). I looked up the documentation, and a letter declaration from the head of the university physical plant provided overall information on the production of the plant and the share of biomass used. There was a long history they could point to, and plans to increase the percentage going forward to reduce CO2Carbon dioxide production. This was also represented in the cost calculations of EAc1 of course.
Thanks Marcus and Scott, I appreciate your comments.
I am currently in contact with GBCI. GCBI acknowledges the existing guidance covering this topic is not entirely clear. They have asked me if the biomass would be harvested from a site that is in close proximity to the project site; additionally they asked if the biomass would be harvested by the owner of the building or purchased from a vendor. The harvesting site is relatively close to the project site (within the same country -Kenya) however the biomass is harvested by another owner.
Upon hearing from GBCI I will post the guidance here.
Here is the response from GBCI:
If the biomass is purchased, either one of the following two options is currently available. The same fuel and fuel costs could be modeled identically in both the baseline and proposed case. Alternatively, the baseline may be modeled using a "standard practice" fossil fuel (e.g., natural gas) with applicable costs. At this time, even if the fuel source meets the eligibility requirements of EAc2 as renewable energy, it cannot be modeled as "free" in the proposed case if it is actually purchased. If the fuel source were to be harvested on-site or from the owner's adjacent property and was essentially free to the owner, it would be acceptable to model as free, and to model a different cost rate between the proposed and baseline case for the same fuel.
That makes sense. The case I mentioned above used the same process; it was not “free” to the project, it had a reduced cost as it is mixed into the fuel. Therefore, the energy cost was different for the base case versus the design case for a percentage of the energy used.
In one of our projects, we've 100% naturally ventilated school building, which will have ceiling fans for comfort, a total area of approx 80,000 sqft, Ground + 2 floors. As per the LEED V 2009, we understand even if no cooling systems has been specified, the proposed design must include cooling system modeled identically to baseline design cooling system. Should our baseline case be system - 6 and the proposed case should also consider the same system? And how should we account for the ceiling fans?
Yes technically that is what you are supposed to do. You can also modify the cooling temperature set points so that the system will not operate in both models. If you wish to claim energy savings related to natural ventilation see the appendix in the Advanced Energy Modeling Guide for LEED.
The ceiling fans would be treated as a plug load in the space identically in both models. If you wish to attempt to claim any energy savings you would need to do so as an exceptional calculation.
We're working on the certification of a restaurant where the kitchen has an outdoor air (OA) rate of 2350 CFM, supply air at 8000 CFM, and an exhaust rate of 3675 CFM. eQUEST treats the difference between exhaust air and outside air as additional outdoor air requirement. The input summary (SV-A reports) shows that both the zone and as a result, the building are taking in roughly 1325 CFM extra outside air. Is there a workaround to this?
The design intentA written document that details the ideas, concepts, and criteria that are determined by the owner to be important to the success of the project., I'm told, was to pull in the make up air for the difference from the four adjacent HVAC zones and not necessarily through the same zone as outdoor air.
Does the OA come through the hood or is it delivered to the kitchen through the HVAC system? If it comes through the HVAC then a potential workaround would be to set the exhaust in the kitchen to match the OA delivered to the kitchen but make sure to account for the extra fan power needed for the actual exhaust. Use the kW/cfm as calculated based on the OA cfm and the actual exhaust fan power as it was designed. The extra cfm coming from the surrounding zones would just be assumed to be relieved within those zones by eQUEST.
I am working on a project in Tokyo, Japan. They are considering saving part of the exitsing building structure for multiple reasons. The fact that you gain more LEED points under EAc1 for energy savings on existing buildings than on a new construction building is a important factor in this decision. How much of the existing building structure needs to be saved in order to qualify under "Existing building" for EAc1?
You do not necessarily gain additional EAc1 LEED points. You may depending on the building type and what was there before. The language in the standard does not refer to structure per se. This is a grey area without a definitive answer that I know of. In your particular case I can't even offer an option without more detail on the existing construction.
I agree with Marcus, it is tough to answer. In most of our cases, it has been pretty obvious; significant interior renovations with limited wall or envelope changes. Sometimes you have to fall back on common sense. In my opinion, and it is only my opinion, the intent of have lower thresholds and steps for renovations was to address the difficult financial issues related to this kind of work. Replacement of windows and roof insulation can often be improved, but no always. If replaced, windows will normally perform well thermally, but new openings are quite expensive, so options for daylighting are very limited. That means in most renovations, many of the tools in our kit are not available or extremely limited.
Thank you for the responses. I recongize that this a gray area and difficult to respond accurately. I also recongize the intent of the credit, but I'm trying to understand on if the project for EAp2/EAc1 would be considered under New Construction or Existing Building Renovation. The plan is to demo the majority of the existing building, but we are hoping to save as much of the existing foundation and below grade structure as possible, and then build new from ground up. Therefore, technically this is a major renovation of an existing building because some of hte building is saved. But it is probably less than 20% of the existing structure. Therefore, is there a threshold % of existing building that needs to be saved in order to say the project is an existing building for EAp2/EAc1. I hope this helps to provide more clarity and would greatly appreciate any support if you know there is a % threshold to qualify the project under teh Existing Building qualifications for the energy related credits.
I know of no published percentages. My recommendation with this specific a question and concern is to contact GBCI and ask for a conference call. If they do not want to give you specific guidance, they certainly would help you form 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 on this topic. Note that if you do a CIR, you should not state a question as much as state what you feel complies with the intent of the credit, with specific numbers, and why you feel this meets those intents. Those seem to garner the best responses.
What you describe is new construction in my opinion. It is not a major renovation; it is a demolition and replacement. Once you tear it down it is no longer existing. I do not think what you describe is within the grey area I mentioned. You could probably claim "existing" for the below grade walls assuming you retain them. Anything above grade is clearly new construction.
We are designing a 4 story building where the owner will occupy 3-1/2 floors of the building and another tenant will at some point occupy the remaining portion. Per the reference guides, this falls under the New Construction (in lieu of Core & Shell) because the owner/developer occupies more than 50% of the building's leasable square footage.
Our question is regarding what is required in the baseline and proposed energy modeling to account for the other tenants, particularly in regards to the mechanical system, power loads, and lighting. This space will be left empty except for limited mechanical systems to prevent fire sprinkler lines from freezing and a handful of light fixtures so that the space can be shown - so do we model these few units as designed/installed? Or do we model the space as it might be per CS Appendix 2 (Core & Shell Energy Modeling Guidelines)? Or do we exclude this space altogether?
Our owner/developer space includes a LED lighting fixture design throughout. If we are required to model the "other tenant" space are we allowed to model the baseline with typical fixtures and the proposed with LED fixtures?
The entire building is served by a variable refrigerant flow (VRF) zoning system so is it safe to assume modeling the baseline/proposed designs similar to how the owner/developer space has been designed?
We had a similar situation with an owner occupied building and part left unfinished for a future 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.. It was also a VRF system. My recollection is that we modeled the building as it was expected to be at final fit out, and that worked out all right.
If the systems have been designed or there are requirements in the tenant lease agreement you can model the proposed as designed. If there is no design or lease agreement related to these issues then those spaces must be modeled in the proposed identically with the baseline. So basically you follow the CS Modeling guidelines.
In my models (both proposed models and baseline models) the surfaces of the zones are from the inside edge of the external walls to the center of the internal partitions. Therefore the internal partitions are part of the building surface area. Is it correct? Shall I do some pre-processing in excel to calculate the surface for the lighting power of the baseline model or for the ventilation rates of the baseline model or for something else (actually now I have little time to change the geometry of the model...)? I use the Space-by-Space method and section 9.6.1 states: "b. For each space enclosed by partitions 80% greater than ceiling height, determine the gross interior floor area by measuring to the center of the partition wall." The partitions of my model are all from the floor to the ceiling.
Moreover section 9.6.1 states: "Include the floor are of balconies or other projections." Does it mean that if a hotel room is provided with a balcony I can assign a lighting power density equal to 12 W/m^2 also for the balcony?
Yes the partition walls are part of the gross interior floor area. Doesn't make a bunch of sense to me but that is what it says. So using the center line of the interior partition is the correct way to do the models.
You would only include the balconies or other projections if they are enclosed, interior spaces. Otherwise they are exterior spaces.
I'm looking for some guidance on modelling a heating system for a new school extension that will be served from the existing boiler system.
One of the options for a new school extension is to utilize the existing building's heating plant which has sufficient capacity, rather than installing a separate heating system for the extension. To what extent does LEED require me to model the existing heating plant? Do I have to create a model of the existing school and populate it with all related inputs such as constructions, occupancy, internal gains, schedules etc? Then, when I run the simulations for LEED, I exclude all of the existing building's energy except the energy relating to the heating plant and add this to the extension's total energy consumption? What are the baseline requirements?
Your help is greatly appreciated.
We faced a similar issue on an addition to a college building several years ago. 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. ID#5496 from 11/02/2004; PREREQUISITE/CREDIT: EAC1 - OPTIMIZE ENERGY PERFORMANCE; RATING SYSTEM: NEW CONSTRUCTION
I think this still holds to your situation.
Thank you Marcus.
Other than sharing the monthly energy bills, is there annual reporting / audits that are required to maintain platinum status?
The Green Engineer, LLP
Documentation of EAc1 is completed through EAp2. The same energy-efficiency measures contribute to both credits, with additional measures needed to earn points for EAc1.
Limits on interior and exterior lighting can help in reducing energy loads.
Use daylight sensors to control electrical lighting, reducing electricity use from natural daylight, as well as cooling loads.
Excessive glazing in the name of providing views can reduce energy efficiency. This does not have to be the case, however.
Building systems contributing to energy efficiency are to be commissioned.
Earning this credit helps to realize the operational benefits of energy-efficient design.
Projects using energy modeling for EAc1 can earn points from onsite renewables, while also earning points under EAc2.
The computer model developed for EAc1: Option 1 is calibrated and refined under M&V.
The quantity of green power purchases is based on the energy model created for EAc1, if one is created. Green power does not help earn points under EAc1, however.
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