This credit encourages the use of building systems submeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system). to enhance the ability of operational staff to analyze specific energy loads and to pinpoint potential areas for improvement in system-level or equipment performance. This detailed analysis is not possible through data collected by regular utility meters.
Although submetering can often lead to energy use reductions, the credit does not require you to demonstrate them.
Many teams choose not to pursue this credit due to the difficulties of integrating submeters in an existing system in order to isolate end-use energy consumption, and the cost of installing submetering equipment.
If the project building has existing submetering systems, it probably makes sense to pursue this credit; if not, it can be difficult.If a project building already has submeters in place, it is much more common to pursue the credit. In some situations teams expand the level of submetering as part of the LEED process.
Favorable scenarios for the credit include the existence of a building automation system that can be used to help track and monitor submetered data, or building systems where the majority of the building’s loads are generated by a few larger systems.
Submetering for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. focuses on end-uses such as space heating and cooling, area lighting, and ventilation fans, and on total system consumption, rather than on what types of energy are used. Therefore, earning this credit entails more than simply measuring a building’s natural gas use, for example—unless all the gas is used by one end-use system.
Tenant submetering would not alone qualify for this credit. That said, if there are separate submeters that break down tenant uses even further—lighting, plug load, supplemental HVAC equipment—then tenant submetering might support meeting the credit requirements. Just be sure that you also take into account base-building energy consumption in your breakdown.
A BAS could contribute to compliance with this credit. However, in order for a BAS to track energy consumption by end use, it will have to be connected to building meters and submeters. It is the extent and coverage of these submeters that is the main focus of this credit. However, a BAS can certainly help with the requirement that meters be read "continuously, automatically, and electronically.”
The minimum time interval between measurement points is not established by the credit requirements. The optimal measurement interval may depend on the system metered and the data storage capacity available. That said, make sure that the intervals between measurement points are short, every 15 minutes or less, to ensure that any spikes in system use are analyzed and addressed immediately. And make sure that these are electronically recorded and relayed back to a computer or BAS, because no manual readings or temporary equipment is allowed.
Assess the current level of building system submetering and the feasibility of adding additional submeters for systems that are not already monitored.
If the project building has existing submetering systems, it probably makes sense to pursue this credit.
If the project does not already have submeters, there can be a number of difficulties that prevent teams from pursuing this credit.
Evaluate your situation for any major obstacles or opportunities. There are few rules that are consistent across most buildings.
Develop and record a breakdown of the building’s significant end-use energy applications. This can be performed as part of the ASHRAE Level I energy audit required for EAp1: Energy Efficiency Best Management Practices.
Significant applications covered by this credit are those that constitute 10% or more of the building’s total annual consumption.
For each major end use-use application, compile the expected annual energy consumption, percentage of total annual energy use, and percentage of submetered energy consumption.
Teams may use the energy end-use breakdown that is also required and facilitated through the ASHRAE Level I walk through assessment performed as a part of EAp1. If an alternative breakdown is utilized, ensure that the end uses correlate to the breakdown develop as a part of EAp1.
The breakdown must be completed no more than two years prior to the LEED-EBOM application.
The total annual energy usage reported in your energy-use breakdown must be within 10% of the total annual energy use reported in EAc1. The annual energy use reported for EAc1 is derived directly from utility bills whereas the breakdown reported for this credit is derived from commissioning or auditing activities, utility bills, or spot or other metering.
The energy-use breakdown should be reported in kbtus. Conversion to kbtus of alternate energy units like kilowatt hours (kWh) or therms may be required. Conversion calculators are widely available online to assist with this calculation.
When listing the type of subsystem, use general categories rather than specific system types, manufacturers, and model numbers. This allows LEED reviewers to more easily understand whether your project meets the credit requirements. Examples include heating, cooling, ventilation (fans), lighting, etc.
Tenant energy use is not considered an acceptable end use according to these credit requirements. That said, if the breakdown includes tenant energy broken into additional end uses - such as lighting, plug loads, tenant-owned HVAC - then these can contribute to the overall submetering scheme.
Prior to installing the meters, consider using a submeter vendor to perform an audit to determine which equipment and subsystems are the best candidates for submetering. Factors to consider include the variability of energy use of a given system, the amount of energy it uses, and the ease of integrating submeters to monitor the systems energy use.
Use the audit information to submeter those systems that have highest variability, or systems that have experienced energy management problems in the past.
Electric loads with isolated circuits are often easier to submeter than natural gas equipment because you can monitor a greater percentage of energy use from a single point—which means fewer meters and lower costs.
The ease of isolating consumption per end-use or mechanical system varies with factors like circuit configuration, equipment in use, and system type.
Employ system-level metering covering 40% (for one point) or 80% (for two points) of the total expected annual energy use.
Metering must be continuous and data must be logged to allow for analysis of trends.
No manual readings or temporary equipment are allowed. The submeter must electrically record readings on a ongoing basis.No manual readings or temporary equipment are allowed. The submeter must electrically record readings on a ongoing basis. These readings should be relayed back to a personal computer or building automation system.
The time interval between measurement points is not established by the credit requirements. Consider short intervals between measurement points to ensure that any spikes in system use are analyzed and addressed immediately. The optimal measurement interval may depend on the system metered and the data storage capacity available.
Request suggested measurement intervals from the manufacturer.
Employ software that provides an automatic warning system if data anomalies are identified.
Establish procedures for reviewing and using metered data to improve system performance.
Compile monthly and annual summaries of results for each system covered.
Facility staff should receive appropriate training to help them develop skills for analyzing and acting upon the data gathered by submeters.
Consider using information provided by systems submetering to shave energy use during peak demand hours when utilities charge higher rates.
Calibrate meters per the manufacturer’s recommendations, and maintain calibration records. (If the meters are owned by a utility or other third party, you are not required to track this.)
Excerpted from LEED 2009 for Existing Buildings: Operations & Maintenance
To provide accurate energy-use information to support energy management and identify opportunities for additional energy-saving improvements.
Develop a breakdown of energy use in the building, either through EA Credits 2.1 and 2.2 or by using energy bills, spot metering or other metering to determine the energy consumption of major mechanical systems and other end-use applications. This analysis of major energy-use categories must have been conducted within 2 years prior to the date of application for LEED 2009 for Existing Buildings: Operations & Maintenance certification.
Based on the energy-use breakdown, employ system-level metering covering at least 40% or 80% of the total expected annual energy consumption of the building. Permanent metering and recording are required. All types of submeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system). are permitted.
Demonstrate that system-level metering is in place covering the percentage of total expected annual energy consumption of the building as outlined in the table below.
Demonstrate that the number of the largest energy-use categories from the breakdown report outlined in the table are covered by at least 80% (i.e., if energy use in the 2 or 3 largest categories is each 100 Btus/year, at least 80 Btu/year in 1 or 2 of them must be metered).
Identify, through an energy audit, building commissioning or some other means, how the building systems are consuming energy. Based on the energy-use profile, develop a metering plan to capture the most significant building loads. Use output from the meters to identify any changes in consumption and opportunities for energy-saving improvements. Have a plan for periodically inspecting the data.
This case study discusses the benefits of submeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system). at a university including the cost and process of adding submeters.
This article provides best practices and information related to the integration of submeters in an existing building.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems.-2009 EA credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
Version 3 forms:
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions for these forms; for more information, visit LEED Online and click "Sample Forms Download."
Hi all, I'm confused about when OR over what period of time does the breakdown need to capture. I understand that it needs to roll up to the EAc1 declared annual energy use (mbtu). Does that mean we need to compare it with 1 years worth of metering data of the systems being monitored? OR is it a one time snapshot normalized and estimate over the year.
If the requirement is 1 year of data, what if we do not have 1 year of data?
Thanks in advanced for the help
The consumption should be based off of one year of energy data, and the total annual breakdown of consumption should be fairly close to what is represented in EAp2 as the total annual consumption for site energy use.
Ideally, this breakdown would be completed using actual consumption data, using existing submeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system). and spot submetering where available, and performing engineering calculations to determine breakdown.
Using a known database, such as 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., could be a good place to begin the process of developing the breakdown but in our experience, an acceptable breakdown needs to be supported by more detailed analysis of actual building use such as spot metering.
We have a meter that measures: chiller + pump + lighting system.
Since we are not discriminating by "end use": would this meter qualify towards this credit?
It doesn't appear that this meter would qualify. You would have to meter at the end-use or by the major system type.
Our project building has central air-handlers, which provide heating and cooling for the tenant spaces i.e. heating and cooling by air only. Do we need to install airflow meters in each tenant space in order to measure the heating and cooling energy provided for each tenant? Some tenant spaces are served by constant airflow and some have VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas.-boxes.
This is a funny credit, where it requires you to measure systems and / or end-uses, which is a little confusing.
First off, you definitely don't need to install metering at the tenant-level, as this is not the intent of the credit. Additionally, the credit does not necessarily require teams to measure all energy uses downstream of an associated system / end-use level, but rather typically requires the main upstream system / end-use to be measured - in this case, the central AHUs.
That said, I'd wait to install metering until you've performed the energy breakdown that is associated with EA Prerequisite 1. If you find that the AHUs are one of the top users, then installing meters at the central air-handlers would help to earn this credit. But make sure to cross check the other credit criteria and metering requirements prior to submitting.
Let me know if you have any other questions,
I am wondering if a commercial building, where over 90% of the building is submetered tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. would qualify for this credit. There are separate submeters for the tenants plug load/lighting and the AC usage.
This sounds like it might work, as long as the aggregate of the sub-metered data covers 40% of the total annual energy consumption and 80% of the largest energy use category, based on the energy use breakdown. But you also need to take into account base-building energy consumption in your break-down.
Let me know if you have any other questions on this - the energy end-use break-down seems to be a driving point to achieving this credit.
If we had to meter things like hot water usage and chillers on a building level to comply with EAp2/c1 to do building-level metering of all incoming energy inputs, would we automatically be able to comply with EAc3.2? (Assuming that the chiller or boiler was 40% or more of total annual energy consumption).
Is this permanent metering or spot metering? And why did you need to do this to comply with EAp2 / EAc1 (I'm just curious on the second question)?
This is permanent metering and we did so because I'm on a campus where we have district heating and cooling and we needed to measure building-level steam, hot water, and chilled water usage as applicable at the building level. In some cases that meant metering at the system level.
I've got a doubt about the time that we should develop the breakdown of energy.
The guide says: "This analysis of major energy-use categories must have been conducted within 2 years prior to the date of application for LEED 2009 for Existing Buildings: Operation & Maintenance certification."
Do I have to conducted this analysis before the project has been registered or before the submission of the project?
Our project team is working on LEED EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. certification of an industrial compound, and there is a question we are not so sure about and we believe one of you may be able to help. The company which owns the compound we are working on has plans to install meters in the buildings located inside of it, to earn credit EA 3.2 – Performance Measurement: System-Level Metering. However, there are three buildings within the site, and we are wondering whether we will have to install sub meters for all main energy-consuming systems in each building or we can install general sub meters for the main energy-consuming systems of the compound as a whole (which would be easier). We are asking you this because each facility has its own energy distribution characteristics and we believe it will not be worth installing the 79 meters they calculate, for the costs they will pay. Is there any reasonable solution we can apply to earn this credit?
This is a great question. While I don't know much about the energy production system at your site, I'm assuming that there is some sort of central plant serving all three buildings. Is this correct?
If so, then you would have to have some sort of metering in place to quantify the percent of energy output of each system is going to each of the three buildings - this would be required to meet the energy benchmarking prerequisite, EAp2.
If this is the case, then you may already be meeting the credit criteria and intent, depending on the types of systems located within the central plant and how much of the overall building consumption these meters are covering.
In this scenario, I would say the safest bet is to submit 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 for this approach to GBCI prior to submitting your project and see if they view this as an acceptable approach.
Good luck and let me know if you have any other questions!
Does anyone have any experience with tenant sub-metering and compliance with this credit? The sub-meters will be arranged to monitor the lighting and plug load energy use of each suite throughout the building. By the letter of the law it seems that EAc3.2/EAc3.3 requires that all sub-metering is broken down by energy use categories and not by end users. It is my feeling however that tenant sub-metering would still meet the credit intent. It allows building tenants to be billed directly for their energy use and, in turn will promote responsible energy management. Finally, tenant sub-metering of lighting and plug loads together is allowable in LEED-CI EAc3.
Before I send through 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 I thought I'd see if anyone could pass through some insight.
I feel that your approach sounds acceptable, and I even gave similar guidance to someone above. I think that language about the end user is to disuade people from submitting just because they meter individual tenant spaces (that would be the end-user bit).
But you'll need to verify that lighting and plug loads meet the minimum percent of total energy use. And depending on the building type, those systems are often low consumers.
CIRs are always a safe bet, even with their price tagLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system..
For natural gas metering applications, is continuous logging of instantaneous flows a requirement? Most meters just put out totalized pulses, so I'm assuming that's fine...
Would a building automation system qualify as the submeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system). system if it could track energy consumption by end-use?
Hi Matthew -
A BAS could be part of compliance with this credit. However, as I'm sure you know, in order for a BAS to track energy consumption by end use, it will have to be connected to building meters and submeters. It is the extent and coverage of these submeters that is the main focus of this credit. However, a BAS can certainly help with the requirement that meters be read "continuously, automatically, and electronically" (p. 199 of the LEED Reference Guide for Green Building Operations and Maintenance). Other electronic monitoring systems can serve this function as well.
If the BAS tracks run time of Air Handlers, is it possible to derive their energy use by comparing run time to the unit's rated energy consumption? This would be much cheaper than submeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system)..
I'm not sure that would fulfill the energy metering requirement Nell. I'm concerned that if you multiply the rated energy consumption by the run time you may get inaccurate results. For example, the compressor in the AC unit may not run all the time, or the fan may ramp up and down with a speed drive or pressure fluctuations on the system. This method would only work if the air handlers ran at factory-tested conditions every time they were turned on.
Is it possible to get a determination from the USGBC if they will accept BAS "virtual meters," such as:
- Spot-measured, constant-load motors with integrated average runtime recorded every 15 minutes; or
- kW signals from VFDs, chillers, etc. with integrated average values recorded every 15 minutes?
And the list goes on. I believe there is a good argument for meeting the intent of this credit using these techniques as long as the "meters" are fairly accurate, but more importantly that they are repeatable for reliable (comparative) management purposes.
Anyone in a position to gain such a determination?
"Anyone in a position to gain such a determination?"
You are, if you have a registered LEED project. Submit a credit interpretation request.
Use the breakdown of energy use generated for EAp1 as a basis for system-level metering for this EAc3.2.
System level meters can be used in the ongoing commissioning process and may expedite the use of in-house staff to perform ongoing commissioning activities.
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