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 EAc1, Option 2: Compliance with Advanced Energy Design Guide, but it is earned automatically and does not carry any additional requirements over EAp2. This option is available to K–12 schools up to 200,000 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 location. For example, evaporative cooling is very effective in a hot, dry climate but is not likely to be a good idea in the damper Northeast or Northwest.
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.
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.
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.
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 Schools 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 all the prescriptive measures identified in the Advanced Energy Design Guide for K-12 School buildings. 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.
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 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.
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 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.
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 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.
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.
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.
In your supporting documentation, include spec sheets of equipment described in the Option 1 energy model or Options 2–3 prescriptive paths.
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.
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.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each Schools-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."
Documentation for this credit can be part of a Design Phase submittal.
For LEED v3 (2009) SSc8 - Light Pollution Reduction, the baseline exterior lighting power allowance uses ASHRAE 90.1-2007 Addendum i (which has similar values to 90.1-2010). I've read other threads that say it's ok to use ASHRAE-2007 Table 9.4.5 without the Addendum for the purposes of computing exterior lighting power allowance in a baseline energy model. Does anyone know of 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 or any other official documentation that addresses this?
Not sure about an Interpretation.
You can use Addendum i for SSc8 but you do not have to use it for EAp2. Make sure that the Proposed exterior lighting is consistent and that you have used the same areas to do the calculations for the Baseline to ensure consistency. The Baseline wattage will not match and that is OK.
Does anyone know of groups who offer donations for energy modeling? I am working with an NGO in a third world country to get their LEED certification on an extremely sustainable building, but the energy modeling is pricey. We could really use the 19 points!
I don't. I think you would have the most luck having the NGO approach firms doing energy modeling seeking the service on a pro bono basis.
I would suggest approaching one of the larger firms. Small firms like us would have a very hard time donating such a large amount of time.
Can I include the Elevators (Lift/Escalators) in EAC1 credit calculation using the whole building simulation method?
I was told by an Elevator supplier that Regenerative Converter in lift could be beneficial while targeting the LEED EAC1 credit due to below reasoning,
“Although the power generated during traction machine operation is usually dissipated as heat, the regenerative converter transmits the power back to the distribution transformer and feeds it into the electrical network in the building along with electricity from the power supply. Compared to the same type of elevator without a regenerative converter, this system provides an energy-saving effect of up to 35%.
And this could be one of the Energy optimisation strategies that could be included while running the whole building simulation method for LEED EAC1”
I would appreciate if someone could share some thoughts on this issue.
Yes you can claim savings for elevators. Establish the baseline in your area based on standard industry practice for your building type in your area. You will need to make the case that the baseline is reasonable. Then claim savings from that baseline as an exceptional calculation.
We also have a project where we hope to get EAc1 credit for regenerative elevators. Where you successful in documenting the savings and do you have any advice for backup documentation?
Is it required in the EAC1 energy model to perform the baseline building rotations of 90, 180 and 270º for an existing building that is being renovated provided the building footprintBuilding footprint is the area on a project site used by the building structure, defined by the perimeter of the building plan. Parking lots, parking garages, landscapes, and other nonbuilding facilities are not included in the building footprint. and exterior walls are not being changed?
No need to rotate an existing building.
There is penalty in our local electricity company's rate structure, for each kW you are over your base demand, so can we include this penalty in the saving we got in the modelling then?
E.g. proposed building peak demand is 5000 kW, baseline is 6000 kW, and there is a $1 fine for every kW over the set demand.
So can we set the demands for both the proposed and baseline models to be 5000 kW, and claim the additional $1000 fine as our savings?
Or we can only set the demands to be 5000 kW and 6000 kW in proposed and baseline building respectively, and the penalties incurred in both cases are minimum?
That does not sound like it would be allowed as you described but there is insufficient detail in your post to say for sure.
You must model the same electric rate in both models. You can enter a simple cost/unit as a rate or enter a complex electric tariff. If this"penalty" is part of a published tariff you can use the entire tariff but can't use just part of it.
It is a part of the tariff, which is stated very clearly as follow:
There is a base demand charge that is agreed, in kW value, between the utility company and the customer. Every month the customer purchase electricity from the company, if the monthly peak demand goes above the agreed kW, if it is over, but <110% (10% overuse), you will pay double the demand charge for the overuse. If the overuse is more than 10%, the demand charge would be tripled.
Take the original example in my question (assuming demand charge is $200 per kW):
Electricity base demand agreed: 5,000 kW
Monthly base demand charge = 5,000 kW X $200 = $1,000,000
If the peak demand is 5300, which is > 5,000 kW, but < 5,500 (110%) kW, the total demand charge is = $1,000,000 + 300 kW X $200 X 2 = $1,120,000
If the peak demand is 5800, which is >5,500 (110%) kW, the total demand charge is = $1,000,000 + 500 kW X $200 X 2 + 300 kW X $200 X 3 = $1,380,000
Obviously the baseline model's peak demand (e.g. 6000 kW in my original question) will be more likely to be higher than the proposed model, so if the base demands are set to be equal in both cases, baseline model will have to pay a lot more, hence more savings.
As long as it is part of the tariff and you use the whole tariff in the model you can claim the savings. The word "fine" threw me a bit since I am sure the utility would not use that term. I would suggest you provide a copy of the tariff when submitting your modeling results.
There are similar charges in electric tariffs I have run across. Some are referred to as a ratchet, they are often set on seasonal peaks. For example the summer peak (May to September) demand can set the peak demand for the rest of the year. So these demand penalties do occur. There are also declining rate blocks based on the demand level (the higher the demand the more expensive kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu. you buy). So these charges based on demand levels are not uncommon. Out of curiosity how is the kW limit agreed to? Is there a negotiation or does the utility dictate it?
Well, you simply tell the utility company what your demand would be, I think you need to tell them in the application form for the installation of the meter.
Thanks for the help Marcus, you're the man!!
Project K-12 school, The enegry calculation done for the entire building but the process enegry cost comes less than 25%.
What is the next step should I provide the supporting documents (Narrative) in the tempete is good enough?
You will need to provide a narrative and ideally supporting calculations to demonstrate the actual projected plug loads. Most often a spreadsheet is provided with a room-by-room calculation of this load.
Client is adding greenhouse to the school project - sort of late in the game. Does this space get included in our energy calcs? I am assuming yes and that there is no way around it.
Your assumption is likely correct. If it is within the scope of the LEED project it will need to be modeled.
So is it getting built as part of the scope of the LEED project?
If not then you can ignore it.
If yes then ultimately the energy model should be based on what was built. I assume by then you will know the answer to all your questions. We typically defer the energy model submission until the construction review so that we do not have to do it twice (once based on the design documents and again following construction). If nothing changed during construction then no problem but if it does change then you are supposed to change the model even if it was previously reviewed and approved.
For the purposes of evaluation during design you may need to make assumptions until the design is complete. You do not exclude it simply because you do not currently have the answers to the questions you raise.
On May, 26 I was listening to webinar regarding Richardsville NEZ school presented by Joanie Hendricks, Public Relations Coordinator from Warren County PS, Tim Murley Superintendent WCPS, Kenny Stanfield, AIA, Architect, Sherman Carter & Barnhart.
On page 39 of slide presentation they mentioned that "The HVAC uses heat sensors to determine how many people are in the room and can adjust the temperature for minimal usage."
Anybody knows what kind of sensor controls (manufacturer, brand) for HVAC are used in this school?
I note that the list of presenters does not include a mechanical engineer so the quote could be a bit confused (no offense to the architects and school personnel out there :-) ).
Am not familiar with that school but the "heat" sensor is probably an infrared sensor(s) (like the ones which turn the lights off). Also likely the sensors control air flow and/or outside air if the space is unoccupied not temperature directly. To detect the number of people in the space a CO2Carbon dioxide sensor is typically used to control outside air flow (also called demand controlled ventilation).
Maybe this is a new technology I am not familiar with and if so I would also love to hear more.
The electric company for our school project offers a rate structure which includes a lower rate for heat pumps. About 2/3 of the building will be served by heat pumps, so we would like to take advantage of this. The rate only applys to the heat pumps themselves, they need to be metered separately. We would like to include this in our energy model, because it provides more advantage over the baseline, which is packaged 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. with hot water reheat.
Our concern is the PRM guidelines say the same rates need to be used for the baseline and proposed buildings. Has anyone had experience with a similar rate structure?
The rate must be the same in both models but you can model the incentive rate in both models which is typically done for off-peak incentives. For the rate you describe this may not show much savings. I would attempt to submit it as an exceptional calculation. Do two proposed building runs, one with and one without the incentive rate. The difference is attributable to the rate and you could argue that the savings are legitimate. Weak link in your argument will be the longevity of the rate's availability.
Our project contains a new LEED Building (addition) and Non-LEED Building (Existing, not in LEED Boundary). The school is looking into cross-tying the DDC controls (only) for the HVAC system for both portions in the new LEED Building. Is this accpetable per LEED as long as the 2 buildings have independendent energy use? There will be no energy impact here.
Yes, I would say so. If you already have the understanding that the addition can be certified by itself and comply with the MPRs, then I don't see how some control integration would really change the picture that much.
In LEED, energy savings are calculated in monetary amounts rather than energy units. I'm working on a project in Europe where feed-in-tariffs are the official energy rate for energy produced from solar PV panels, which is at a premium to regular electricity rates. Since PVs would contribute to savings in kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu., but an even greater savings in monetary units, how should this be treated when modeling in the baseline versus the design case? For EAc2?
You have two options to calculate renewable energy cost. Use the virtual rate calculated by the energy model for EAc1 or the local utility rate structure. There is an option on the LEED Online form to select one or the other. Sounds like you are better off using the local rate structure. The same cost value should be used in both EAc1 and EAc2.
My project received the following Technical Advice offered by GBCI, "NOTE: At this time, 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. for this credit is not available, per the LEED for Schools 2007 Reference Guide. However, the USGBC is in process with issuing an errata noting the acceptance of exemplary performance for this credit." Does anyone know if any errata has been issued? I cannot find it for LEED for Schools 2007 on USGBC's website; only for LEED for New Construction v2.2.
The current LEED for Schools errata sheet was last updated in 2008 so it does not look like it is being updated regularly. If it is allowed in NCv2.2, then the reviewer should grant it in LEED for Schools too. In your reply tell the GBCI reviewer that they are not correct. If the credit is denied in the final review follow the instructions in the email received from GBCI for challenging a final review.
Karen: This is a result of the Minimum Program Requirements (specifically, #2, Must Be a Complete, Permanent Building or Space) , which are new to LEED 2009 rating systems. You can read more about them along with the supplemental guidance, here:http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2102.
The supplemental guidance talks about the reasons behind each MPR - this might be helpful to you.
Cara: Yes, thanks, I did know that. Our school system is required by State Law to meet LEED Silver and I don't think we can meet even some of the prerequisites if we have to include an existing part of the building. I understand the thinking behind this MPR, but it does not make sense to renovate a six year old classroom addition. Unless we find some flexibility on the part of the LEED review teams, we'll have to seek a waiver from the state.
I'm curious which prerequisites you don't think you can meet? EAp2? IEQp1?
To be clear, you're not required by LEED to renovate the addition, just to include it in the various LEED credit calculations and compliance documents. Reusing the building could help you with some MR credits.
Tristan: I'm worried about EQp3 Minimum Accoustical Performance. Our classroom additions were not built seven years ago with any thought to STCSound transmission class (STC) is a single-number rating for the acoustic attenuation of airborne sound passing through a partition or other building element, such as a wall, roof, or door, as measured in an acoustical testing laboratory according to accepted industry practice. A higher STC rating provides more sound attenuation through a partition. (ANSI S12.602002) ratings. I'm also concerned about EAp3, but I'm not a mechanical engineer so don't know how that might affect us.
EAp3 is pretty easy, and for a seven-year-old buliding I think you'd be fine.
Why don't you post about your situation over on the IEQp3 forum? It's an interesting situation.
I'm told that the GBCI review teams evaluating LEED for Schools 2009 projects will no longer allow a portion of a project that is scheduled to remain untouched to be excluded from the LEED Boundary.
We have a number of schools now in feasibility stage with recent additions of gyms or classrooms that we would not plan to address in the modernization. If we can't exclude them, we may have a hard time meeting our mandated LEED Silver level certification.
Anyone else have an issue with this?
We are working on an elementary school project and we're trying to correctly model the sun shading. We understand we should "count" the benefits from permanent sun shading devices designed at windows (for example, projections from the building). We also understand that you cannot "count" any shading benefits from adjacent buildings on neighboring sites (because perhaps that other building will be torn down in the future).
However, we believe we should model the shading effects on our own building. In other words, one wing of the school is 2 stories and the other wing of the building is one story. The two story wing will shade the single story wing for at least part of the day. Is this considered adjacent building shading? Or, can we submit it as "self shading".
We are modeling the project using Trane Trace which calls building shading "adjacent building shading"- which is not to be counted by LEED. We've categorized it as adjacent building shading simply because Trane Trace doesn't have a "self shading" option.
Is self shading a legitimate strategy to demonstrate projected energy savings? And, if so, how can we communicate to our reviewer that we really mean "self shading" and not "adjacent building shading".
And no, there is no way the 2 story wing of the building will ever be demolished.
Any help is appreciated.
Self shading is definitely a legitimate strategy. Some software packages can pick this up "automatically". I don't believe Trace has that capability.
I would do just what you described above, and include an explanatory narrative in your LEED submission.
On Demand Water Heaters
Any advice on how to capture savings from these devices in energy modeling? Our engineer is struggling.
The baseline is required to use the same type of equipment so the only savings you can capture related to this equipment is the difference in efficiency between the proposed water heater and the baseline defined in ASHRAE 90.1-2007 Table 7.8.
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.
Do you know which LEED credits have the most LEED Interpretations and addenda, and which have none? The Missing Manual does. Check here first to see where you need to update yourself, and share the link with your team.
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