Building Performance Monitoring and Evaluation
The Building Technologies Office (BOT) at DOE uses performance metrics to standardize the measurement and characterization of energy performance in commercial buildings. These metrics help inform the effectiveness of energy efficiency measures in existing buildings and highlight opportunities to improve performance.
Performance Metrics Objectives
Performance metrics deal with building energy consumption and on-site energy production. To be useful, the commercial industry must agree on standard definitions for these metrics and share consistent procedures for collecting and reporting data as well as ensuring data quality.
BTO established definitions for the following performance metrics and procedures:
- Standardization: Standard definitions provide a consistent basis for comparing energy performance among buildings.
- Versatility: The analysis is customized to the facility boundaries, energy configuration, analysis goals, and analysis budget of specific projects.
- Efficiency: Data collection is carefully matched to the analysis goals and study questions, avoiding the common pitfalls of too little or too much information.
Implementing best practices in operations can significantly improve building efficiency. Today’s technologies create unprecedented energy data for analysis and action. The performance of building systems, operational changes and maintenance efforts can be tracked over time. These technology tools will be transformative if we continue to evolve our energy management practices, review the data, build our plans and act on new information. The goal? Bringing people and technology together to improve building performance.
Featured Case Study
Author: Building Efficiency Initiative
Much stems from the misconception that building efficiency projects are costly and complex, maybe even boring. Little noticed is that multiple transformative innovations in building technologies have become mainstream options over the past decade. They can improve comfort and productivity while curbing energy use and saving money.
Performance Metrics Tiers
The performance metrics defined above by the Commercial Buildings Integration Program offer different tiers of information to address the needs of various users. Energy performance is measured throughout the life of a building, from design to commissioning to ongoing operations. To be effective, the measurements and resulting analyses should be consistent at all stages. The Commercial Buildings Integration Program (CBI) has defined different levels, or tiers, of energy performance metrics to address this concern. Below you will find information about the various goals users are trying to achieve by using performance metrics and the tiers of metrics.
Many individuals and groups are involved with a building over its lifetime, and all have different interests in and requirements for the building. Although these interests differ, the value in using metrics reflects a small number of driving factors:
- Controlling energy costs and energy consumption
- Minimizing environmental impacts
- Enhancing the image through marketing
- Improving load forecasting, energy management, and reliability
Tiers of Metrics:
Tier 1 Metrics
The metrics available at Tier 1 represent the most basic level of a procedure yielding fundamental results. General characteristics of a Tier 1 analysis are that it:
- Generally yields only monthly and annual results
- Often requires only existing data, including utility bills, building drawings, and a physical examination (walk-through) of the building
- Typically does not require additional metering equipment.
In Tier 1, utility bills and other rapid, inexpensive means of data gathering are used to determine monthly and annual purchased energy, electrical demand, facility energy production, and related metrics. Tier 1 analysis compares annual facility energy performance. A Tier 1 analysis may or may not describe building energy performance, depending on other energy uses at the facility.
Tier 2 Metrics
The metrics available at Tier 2 represent the advanced level of a procedure yielding detailed results. Most analysts who are interested in a detailed examination of a building’s performance will perform a Tier 2 analysis. General characteristics of a Tier 2 analysis are that it:
- Yields seasonal, daily, hourly, or subhourly (if appropriate) results
- Yields results itemized by type of end use
- Requires new data to be recorded in addition to existing building data
- Generally employs submetering and a data acquisition system (DAS).
A Tier 2 analysis must be performed for end-use energy totals or predictions of savings from changes in systems. A Tier 2 analysis can require a substantial effort, and its benefits should be weighed against the associated costs.
Managers and policy makers use the data collected in Tier 1 and Tier 2 analysis to derive indicators. Indicators are used to communicate general trends. They are often used to set policy and demonstrate progress toward goals. Indicators are also useful to identify areas of a project that need more attention.
Additional Resources and Key Metrics Reports:
- Procedure for Measuring and Reporting Commercial Building Energy Performance
- Procedure to Measure Indoor Lighting Energy Performance
- Procedure for Measuring and Reporting the Performance of Photovoltaic Systems in Buildings
- Standard Definitions of Building Geometry for Energy Evaluation
- Performance Metrics Research Project—Final Report
- Source Energy and Emission Factors for Energy Use in Buildings
- Buildings Performance Metrics Terminology
- DOE Commercial Building Performance Monitoring & Evaluation Page