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.
Hi, I am starting work on a laboratory building and have been looking at the standards to see how they apply. The project will use both an ASHRAE 90.1 2007 and 2010 baseline building (one of LEED target and the other for separate project target). My questions are:
1) Bypass air to maintain exhaust stack minimum air flow requirements for plume. Can this be classed as process energy as it never goes into the space? I think it is
2) ASHRAE 90.1 2007 says the baseline should reduce exhaust and makeup air volume to 50% of design values during unoccupied periods – If this is not allowed by the AHJ would the requirement to have the full ACHAir changes per hour: The number of times per hour a volume of air, equivalent to the volume of space, enters that space. at all times (or as specified by AHJ) in the proposed supersede this statement for the baseline so the rates match.
1. I believe it's okay to classify fume hood exhaust (or the bypass air for fume hood exhaust) as process energy. However, it might be simpler to include all the fan energy in the HVAC energy. Process energy should normally be the same in the baseline and in the proposed, unless you have a well-documented special calculation showing process energy savings for a particular process.
2. I believe the way to model the makeup air would be to have both the baseline and the proposed reduce the makeup air to 50% during unoccupied periods. This is an ASHRAE 90.1-2007 energy model for LEED, not an energy model to accurately represent the energy use of the building. It's not really relevant that you won't actually be reducing the makeup air to 50% when unoccupied. You still have to model it that way to have the baseline and the proposed rates of ventilation match and to comply with ASHRAE 90.1-2007. (You may do something different for your ASHRAE 90.1-2010 model, depending on the purpose of that model.)
I have a question, we have received a comment from a LEED reviewer requesting for the following information:
"Table 1.4 of the template appears to indicate that all the assembly U-valueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value. for the exterior walls in the Proposed model may not account for the thermal breaks due to the steel-framing portion of the construction assembly. Each construction assembly U-value is not a direct inverse of the insulation R-value for that construction assembly. The R-value of the insulation located between the steel framing must be de-rated when determining the assembly U-value for the exterior wall assembly to account for the reduced thermal resistance of the metal framing components. Revise the Proposed model, as needed, so that all components of the exterior wall construction assembly are accounted for when calculating the assembly U-value for assembly type in the actual design. In addition, update Table 1.4 reflecting the changes. Refer to Table A3.3 in ASHRAE Standard 90.1-2004 for additional guidance regarding how to de-rate the R-value for insulation located between steel framing assemblies."
We have the following wall composition in the project (Based on arch dwgs): 5/8" Gypsum Board + Metal Stud every 24 in O.C. + 8in CMU Block with injected R8 + 5/8" Hardie Board
So we are updating the assembly based on table A3.1A (Ashrae 90.1-2004 Appendix A) with a U-0.125 (= R8 Assembly) however, since this table in my understanding is only accounting for the concrete block, the insulation and the metal framing, I have added the 5/8” gypsum board (layer 1) and the 5/8” hardie board (layer 7) to the modeled assembly as well. Has anybody had a similar comment? How did you addressed it? Thanks.
The appendix a tables already include assumptions about the entire assembly. Make sure to read the beginning of A3.
We are working on a LEED NC 2009 project in Germany with DES which the thermal plants consist 5 boilers and a cogenerator.
We are thinking to follow the Scandinavian DES protocol to replace Option 2 in the DES v2 guidance. According to 4.1-Equation 1:
PEFdh = ∑Ef,hob(i)*PEFhob(i)+ ∑αh,i*Ef,chpCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source.(i)*PEFchp(i) / ∑Qdel,j
The energy inputs in fuel and the delivered heating energy are requested to calculate the total primary energy factor.
The question is, are the energy inputs in fuel (Ef,hob(i), Ef,chp(i)) and the delivered heating energy (∑Qdel,j) the total annual amount or can I take the specific value in kW as planned. So far the DES does not yet exist so we don’t have the annual amounts.
If the total annual amounts shall be used here, then what is the difference between this alternative and the Option 2 in the DES v2, in which the annual energy consumption and the generated energy are also requested to calculate the average heating efficiency.
Any advice is appreciated. Thank you in advance.
I have a doubt concerning the percentage of vertical fenestration I have to consider for Table G3.1 5.c.
Let me give you an example. A squared building has four facades, all with the same surfaces. The percentages of vertical fenestration are:
- facade 1: 60%
- facade 2: 20%
- facade 3: 20%
- facade 4: 20%.
Therefore considering the whole building the percentage of vertical fenestration is 30%.
For the baseline model shall the limit of 40% be respected by every facade? Or only by the average value, considering the whole building?
I am working on the energy model of an renovated building, where only the structure will remain (LEED CS). It is located in a corner, attached to other buildings on both sides. Thus, the orientation is defined.
Should I rotate the baseline model?
How does ASHRAE 90.1 defines an existing building?
For the purposes of Table G3.1-5 (Baseline) (f) I do not think it is an existing building envelop.
Relative to the rotation I think you could make the case that you would not need to perform any rotations since the structure is fixed.
The words in italics within the standard are included in the definitions.
Please see below for comments from USGBC relative to our design submittal for Portland Fire & Rescue Station 21 (1000020729).
We've sent inquires to USGBC several times with no response. Please refer to the last two lines of this message for our request for additional information relative to USGBC's calculations. What is the best way to get this information? Thank you for any help you can offer!
EAc1 OPTIMIZE ENERGY PERFORMANCE - REVIEW COMMENTS FROM USGBC:
08/05/2014 DESIGN FINAL REVIEW
Additional documentation has been provided for EAp2: Minimum Energy Performance claiming an energy cost savings of 30.04%. However, when EAp2 was recalculated based on the issues noted there, the project has demonstrated an energy cost savings of 29.95%.
06/19/2014 DESIGN PRELIMINARY REVIEW
The LEED Form states that the project has achieved an energy cost savings of 30.2%. However, to demonstrate compliance, the following must be addressed.
1. Refer to the comments within EAp2: Minimum Energy Performance and resubmit this credit.
EAp2 MINIMUM ENERGY PERFORMANCE - REVIEW COMMENTS FROM USGBC:
The LEED Form has been revised to address the issues outlined in the Preliminary Review and states that the project has achieved an energy cost savings of 30.04%.
However, to demonstrate compliance, the following new issues surfaced as a result of the response to Preliminary Review must be addressed.
1. The LEED Form Table EAp2-5 was not completed correctly. The Proposed Case energy type for pumps has been left blank and due to this the pump energy consumption is not accounted for in the annual proposed energy consumption. In order to award partial credit the LEED Form has been corrected to reflect electricity as energy type for pump in the Table EAp2-5. For future projects ensure to update all the inputs correctly.
Due to these issues, the revised Proposed Case energy consumption is 160,755 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./year of electricity, and 1,352 therms/year of natural gas, with a revised Proposed Case energy cost of $ 12,069.96/year. This leads to a total percentage improvement of 29.95%, which meets prerequisite requirements.
EAc1 OPTIMIZE ENERGY PERFORMANCE: INQUIRY FROM MEP (Electrical) CONSULTANT:
"Only 0.09% cost saving was denied. May we please have the calculation from the review?"
How have you contacted USGBC? The best way is through the contact us page on GBCI.org. If that is what you did it can take them a few weeks to respond.
This sounds like such a simple adjustment that you should be able to replicate it yourself. They saw pump energy use in the output report from the modeling software that was not on the form and they added it and recalculated the savings. The reviewer probably just added the pump energy use to the form and let the form recalculate the savings.
We are working on a mixed use project with a glass-covered outdoors space that fills the void between 3 different buildings (hotels, conference and restaurant). The space will be naturally ventilated, sun protected and could have some pre-heating.
Since the space does not "belong" to one building, we are wandering what the cleverest way to do the energy models.
Should we simulate all the buildings together?
Would it be better to simulate each building seperately with a kind of thermal "mask" for the other 2 buildings?
(Also, though not the subject of this thread : do we need to register the Winter Garden/Agora for LEED certification?)
Thanks for any tips
Is the whole project pursuing LEED? If so you should look to the Campus Application Guide. If all three are included then you will need to be able to separate the energy use of all three to demonstrate that each complies individually. You can do that with separate models that account for a portion of the shared space or model them all together and separate the building via submeters within the model. The best way to model it is very difficult for me to say as I do not have nearly enough information for even give you any real guidance.
We do imagine a Campus Type Certification (all LEED) so I guess it's our call about whether we do one model (with seperate meters) or seperate buildings.
Do you think that the Agora/Winter Garden needs to be registered as a seperate space within the Campus? There will be some energy use associated with it but we are not clear since it is spans 3 different establishments...
Hard for me to say. I does sound like a separate semi-conditioned space.
Hi, we are working on a LEED NC 2009 project consisting of an office building, where the thermal energy (heating via hot water) is generated and distributed by means of a municipal grid (about 40 million of square meters of served volume) served by thermal plants consisted of turbines, boilers, incinerator and cogenerators.
It is our first case in which we aim to follow DES option 2 (full accounting). According to appendix C of the DES guidance, we need the following information:
- Total annual MBTU of fuel at the plant (using fuel meters);
- Total annual MBTU of hot water delivered to the building serviced by the district plant (using BTU meters)
- Total annual pump energy for the hot water primary loop and distribution loops
We asked to the public authority that and manage the Municipal Energy system but, due to the technical complexity, size of the plant and the employment of distinct typology of fuels our request has been denied except for a global conversion factor between primary and final energy.
The building under LEED certification is designed to achieve high energy performances, for instance it is able to satisfy whole electric energy demand by means on-site site photovoltaic generation.
Despite to an high performing design, it seems that we cannot pursue the maximum score available due the external limitation in terms of plant’s information.
Have you any suggestion to solve this issue?
Thanks in advance.
All European projects can use this other district energy system protocol - http://www.usgbc.org/resources/treatment-scandinavian-district-energy-sy... - have you checked into this alternative?
If this works you owe me a grappa or two.
We have checked the Scandinavian protocol and we have a couple of doubts:
- Can we use directly the PER (total primary energy factor for district heating) coming from the Energy Authority throw auto declaration, without calculate by means of 4.1-Equation 1? Unfortunately, we cannot know energies values in fuel, used for heat production.
- Appendix A gives the specifics Scandinavian primary energy factors for fuels, however Italian factors are different. Therefore, which would be appropriate for our case?
Many thanks, see you soon with a rich assortment of grappa!!!
Ah you are making e earn my grappa assortment! I will have to look at the document in more detail and get back to you next week.
Using the PEFdh provided by the local utility should be acceptable as long as you can document that it was calculated by the utility using the same formula as Equation 1 in Section 4.1. You will also need the greenhouse gas emission factor (Кdh) which must be calculated using Equation 4 in Section 6.1.
You are correct that the primary energy factors for fuels in Appendix A Table 5 (as well as the total emission factors in Table 6) are specific to Scandinavian projects. The values used for other European countries should be consistent with their own regional values. Also note that Equation 6 in Section 8 is based on oil as the fossil alternative because it is commonly available in Scandinavia, but for other places in Europe the most common fuel source for heating is natural gas rather than fuel oil, so Equation 6 should be adjusted to use the local market natural gas price.
I need to document, through LEED NC 2009, my energy savings through the use of a solar water heater. I'm not certain if there is a savings estimating spreadsheet out there for use or not. If so, I'm unable to find it. Also, should I include this in my energy model or document elsewhere when submitted such as Table L-1 within the submittal. Apparently, a calculation method that usees a percentage reduction in service water energy is not sufficient to document savings associated with this system.
We use RETScreen - http://www.retscreen.net/ang/g_solarw.php
Some energy modeling software can model it directly.
Renewable energy is entered in Section 1.8 of the form.
So I would not enter the savings in my energy model because it would be double counted...correct?
Correct you would not also show the savings under service hot water in Table EAp2-5. Report it in Section 1.8.
You can model the savings in your model just do not report it in Table EAp2-5. Do a model with and without and report the difference in Section 1.8.
In the table there is a mention of Path-A and Path-B.
Pl. help as to how to interpret Path-A and Path-B.
Section 184.108.40.206.1 shows a sample Path A calculation. The Path A and B calculations are likely included within the Test Procedure in AHRI 550/590.
I am working on a project where they are proposing a lighting installation forming a piece of artwork. They are asking whether it can be excluded from the LEED calcs.
My opinion is that it can't be excluded per se but should be treated as a process load therefore the same energy use in both the proposed and baseline building but i wanted to get others views on this.
Does it provide the required general illumination to the space? Is there another, separate lighting system which can independently provide all of the required illumination to the space? If the answers are no and yes then it would be considered process.
The interior lighting exceptions are listed under Section 220.127.116.11. If one of these applies then it can definitely be considered process lighting.
I am currently working on a lab facility which has five labs of varying types. Our original intent was to create our energy model only using the base building equipment and technology since the owner's intent is to have a rotating mix of equipment in and out of the facility all year long. The equipment is also being installed under a different contract and while we are providing the fit-ups, we are not connecting the equipment as part of our contract.
However, where its complicated is that the initial (first) equipment will be installed at the time we seek building occupancy, so I want to know if we have to model all of the baseline equipment and the lab equipment knowing that it will be in constant flux.
I have more information if necessary, but I think that gives a good general concept of my question. Hopefully there is a simple answer.
The lab equipment is process equipment, which must be included in the model but is modeled identically in the base and the actual models. You don't necessarily need to model each piece of equipment individually and exactly though. Just include an approximate or estimated wattage for total lab/process equipment in each zone.
The best way to do this is to get the information you need to model this as accurately as you can. The fact that some equipment is outside your contract has nothing to do with it. We typically meet with the owner/occupant to find out what they anticipate being in each space and model it accordingly. You can use general W/sf values from a published source but this is generally far less accurate.
In general your model should reflect what is expected to be installed.
Do I have to chose one categorization procedure (Building Area or Space by Space Method) to determine the lighting power density (LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space.) in the Baseline Energy Model?
My building is Mixed-Use so I have used (MultiFamily LPD 0.7) for the residential units and used (Space by Space Method) for the rest of the building spaces as Gym, Corridors, Store rooms, etc.
Do I need to change it or it might be accepted like that?
In general you must choose one method and apply it to the entire building.
For the residential portion you should follow the guidance in this document:
I'm currently working on a Core and Shell project. According LEED, we can use the Alt Compliance Path for Core and Shell that revises the Points Thresholds based on Owner-Influenced Energy Percentage. We completed the excel spreadsheet form provided by LEED and uploaded to LEED online. However, it seems there's no way that LEED online recognizes the new thresholds based on the provided excel spreadsheet. Has anyone done this approach and please advise on what else do I need to do or how does LEED recognize the new thresholds. Thank you.
Enter the number of points you are pursuing even if the percentages do not line up. Then upload the spreadsheet with an explanation for how you determined the owner controlled/influenced percentage. The reviewer will make sure that the appropriate number of point are awarded.
Marcus, thanks for your assistance. Not quite sure where I enter the number of points. Are you just talking about the scorecard in general? Thanks.
Attempt the same number of points that you would earn using the spreadsheet within the LEED Online scorecard.
We are currently building a school and one of our subcontractors asked if ceiling tiles count towards Energy and Atmosphere Credit 1? I read through the forum for this credit but could not decide if the light reflectance of the white ceiling tile, 0.86%, counts towards this credit? Any help on this would be great
The ceiling reflectance potentially impacts the lighting power density and daylight dimming. So indirectly it counts but not directly.
We have solar thermal system to provide heated water for a swimming pool, sinks and showers. The system has an electric water heater backup system. 1. Should the base system be modeled based on electric water heating? 2. Would the design model have the same electrical energy use as the base case less the solar thermal contribution? 3. Can we claim credit for additional savings for a electric backup system that is more effecient (say better insulated tank and/or water lines), and/or more efficient pumps than teh base case system?
2. All other parameters being equal, yes.
3. Yes. You can also claim credit for reduced hot water demand (i.e. low flow shower heads).
Marcus, Thanks so much for yur replies to my previosu two posts on thsi. i'll have a third on it to post soon but waiting for a few details. Cheers!
Utility rates is a confusing thing for me, I am working on a building that has 9% Retail Area, 7% Church and the rest is a Residential Area.
The Retail Area consumes up to 15% of the Energy thou!.
Do I come up with a Virtual Energy Rate for the whole building (Using the Area% or Energy Consumption%)?
And what type should the church follow when I use the Energy Rates from EIA?
Also, do I use the latest Energy Rate for the State (NY April 2014) or the Annual Energy Rate (NY 2013)?
The virtual rate is the whole building energy cost per fuel source divided by the whole building energy use for that fuel source.
I do not think that the state average rates are broken down by commercial building type. They may be broken down by commercial and residential. You could use either rate.
You could also use the specific utility tariff within the software but that can get complicated.
We are modeling a gym in Guatemala where we will have no heating or cooling system but will have mechanical ventilation. How would we set conditions for the base model VS the design model; the same or differently.
There are no energy efficiency measures such as CO2Carbon dioxide sensors, demand control ventilation, etc.
Model the ventilation identically.
I am classifying my 24/7 elec/comms rooms under G3.1.1 Exception b and therefore modeling them with System 3 - Constant volume packaged roof top air conditioner.
My question is as these spaces aren't really occupied but are 24/7, should the system a) be constant volume 24/7 and vary the temperature to meet the load in the space or b) cycle on/off to meet the load in the space.
Cycle on and off to meet the load.
Thanks in advance for any insight. I have a two part question –
1. I want to confirm that all site lighting within the LEED boundary can and should be included in the energy model. Appendix G specifically states parking garages and building facades but does not mention any other lighting included under 90.1 -2007 Table 9.4.5 LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. for Building Exteriors.
I've done it in the past, but the savings is usually small and has little overall effect, but now I'll come across a situation where it could be substantial.
2. In preliminary scoping we have a project that consist of 15,000 sq building with ~ 125,000 sq ft of parking and drives (large overall site with the building set back substantially from the main access point due to function). Utilizing the LED fixtures the preliminary lighting design has shown a substantial decrease in the LPD from the allowed 0.15 w/sf. Given the size of the parking/drive compared to the building and the 24-hr nature of the facility the baseline site lighting is almost as much as the base-line building lighting and is resulting in an estimated ~ 25% energy savings for the building by itself.
Is it reasonable to expect to be able to claim this entire savings for EA credit? It ‘feels’ like I’m gaming the system, but the actual energy use should be realized. am I missing something?
1. Yes all the site lighting must be included. The credit language states that all energy in and associated with the project must be included.
2. It is not unusual for savings of 75% or more in exterior lighting when using LEDs. You can legitimately claim large savings. One thing you said struck me as odd - the 24 hour nature of the facility should have almost nothing to do with the energy use. Section 18.104.22.168 requires that the exterior lights are off during the day in most cases.
Thank you for the response. I had always assumed that it was expected to include all site lighting, but when I went to double check it was not as clear as I had anticipated - specifically note parking garages and building facades as opposed to "all" site lighting.
It's also good to hear that we don't appear to be in unknown territory with the savings. Our case might just be a case of the large amount of site parking and drives, driving the site lighting to a larger portion of the overall use.
As for the 24 hr comment, it was meant to say the lights were on full throughout the night for security, rather than at reduced levels after midnight which can often be the case once building are closed. Consequently, we are working at 10 -12 hrs a day of operation for ~ 4,000 FLH compared to retail space which may have closer to 2,000 FLH for the parking lot lighting.
Thank you again, I appreciate the feedback and hopefully this helps some one else as well.
I am having problems with the EAc1 template.
The EAp2 and EAc1 reports 2 points for a 12.3% savings of a Major Renovation. (12% = 3 points for Major renovations).
Is it a common problem in the templates? Anyone with a similar problem?
The forms usually get the points right.
If it is 100% renovation then it should earn 3 points.
We have a large institutional project with a small greenhouse facility at the perimeter of one of the classrooms. The greenhouse is part of the building envelope, but the systems are separated to preserve the greenhouse environment. How should the energy model address this piece? It is along the exterior of the building, is it acceptable to exclude this area?
Is the greenhouse part of the current project scope? We have a project with a greenhouse on the roof, but since it's going to be built during the next phase after the building with a different funding structure, we are able to exclude it from current LEED boundary. If you include the greenhouse in the current LEED boundary, you are required to include the greenhouse process loads which is likely to have an adverse effect in your modeling.
If it is in the project it must be modeled. You cold probably argue that it is a process load and model it identically in both models. On a large institutional project the effect should be very, very small.
Instead of asking for exclusions, seek better solutions.
We are dealing with the project served by DES. As client’s goal is to achieve Platinum we are proceeding with option 2 of modelling DES.
Our DES is served with mix fuel ( coal, biomass and oil) for which we calculated fuel mix price as 26,47 $/MWh. Our baseline system is on-site gas boiler for which fuel utility rate is 50,8$/MWh .
As DES guidance is super unclear we have a question in regard to the rates used for calculations:
should we use the same rates for baseline and proposed building equal to = 26,47 $/MWh (as calculated for the fuel mix)? Or maybe ,the same utility rates for base and proposed which are required in DES guide means that they must be consistent in both base and proposed building i.e. if DES will use gas it will be priced at rate of 50,8$/MWh - the same as baseline?
Any comments will be appreciated
Use the same rate in both models based on the rate calculated for the DES.
But thaht don't make any sense, to price gas as fuel mix. Plus it's not showing any benefits of DES over standard boiler.
I thnik that this quidance confirms thaht the rates for base and propose might be diffrent.. What do you think Marcus?
The gas price has nothing to do with it in this case since the DES does not use gas. Appendix G does not say that the Baseline is always gas. The Baseline uses the same fuel as the Proposed in Appendix G.
See G2.4 - the energy cost is determined using the actual rate. The rates applied to each model must be identical. Section 22.214.171.124 of the DES v2 states that the rates must follow the normal Appendix G and LEED protocol.
The DES guidance is set up to account for the impact of the DES. If the system is more efficient than the Baseline you show savings, if not you show a penalty.
In general Appendix G and LEED do not allow savings related to the comparison of different fuels.
The document is certainly not an official document so it does not really matter what it says but it is technically correct. If the DES used gas you use the building rate for the gas (not the DES gas rate) in both models. Since this does not apply to your case and 126.96.36.199 Exception a does apply, you use the central plant rate.
If the biomass is a qualifying renewable you can get credit for that.
Thank you for help
Hi, I am not quite sure how to comply with Appendix G requirement to heat & Cool all conditioned/indirectly conditioned spaces and use baseline system where not designed whilst still staying true to the proposed design. I have 2 scenarios which seem to be causing issues.
Scenario 1 - Spaces which are heating only (E.g locker rooms)
Scenario 2 - Restrooms/stores which have transfer fans
The baseline system is system 7 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 reheat. So I am not sure how I can apply a completely different system to a room with heating only in the proposed. Do i ignore the actual proposed heating coils and match the entire system (e.g cool to 55 and reheat as required using the proposed boiler plant) sizing the airflows/coils as the baseline is sized for both heating/cooling.
The rest rooms are modeled in VE IES Apache HVAC as receiving transfer air from the appropriate rooms. Would these rooms then need to be on another network which uses the baseline system?
Is the baseline plant just sized for these rooms (as opposed the baseline which it is sized for all rooms)
For the heating only spaces I would suggest you apply addenda dn and use a system 9 in the baseline.
For indirectly conditioned spaces in the baseline you model them identical to the proposed using the baseline system. The proposed is modeled as designed.
So i think what you are saying is if you had a restroom in the proposed with exhaust, you would model it as is. Then in the baseline you would model with VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with reheat (if the building was system 7) however the setpoint would be whatever condition the proposed is meeting so most likely there would be no cooling/heating load so the CFM in the spaces from cooling/heating would be zero with just the exhaust as per the proposed (fan power proportion out of the total from the 90.1 equation).
Not sure if you would have no heating/cooling load in the space but the rest of it sounds right. The exhaust fan power does get proportioned out of the total Baseline fan power calculated for that system.
If the proposed doesn't require any heating/cooling they I don't see why the baseline would for internal spaces such as restrooms to meet the same conditions. I am just concerned about penalizing the baseline too much in exhaust only spaces when the proposed isn't conditioning them directly.
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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