Performance Metrics Tiers

The performance metrics defined by the Commercial Buildings Integration Program offer different tiers of information to address the needs of various users. On this page you will find information about the various goals users are trying to achieve by using performance metrics and the tiers of metrics.

Goals in Measuring Performance

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

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. To learn more about the analysis tiers, read Procedure for Measuring and Reporting Commercial Building Energy Performance. You can also view a list of terminology with definitions and examples.

This graphic is titled, 'Performance Metrics Project Activities.' The main image is a triangle that is divided into four sections. The sections are (starting at the base): Data, Tier 2 Metrics, Tier 1 Metrics, and Indicators. The graphic also identifies users who are interested in each level of metrics. Operators, energy professionals, and researchers use Data, Tier 2 Metrics, and Tier 1 Metrics. Designers use Tier 2 and Tier 1 Metrics. Rating system sponsors, energy suppliers, and owners use Tier 1 Metrics. Policy makers use Indicators. The graphic also has an image of a building on the lower left with an arrow pointing from the building to the Data layer of the triangle. This arrow is labeled 'Monitoring Procedures.' There are two more arrows outside of the triangle - one points from Data to Tier 2 Metrics, the other points from Data to Tier 1 Metrics. Both arrows are labeled 'Analysis Procedures.'

The Commercial Buildings Integration Program defined different tiers of performance metrics to address the needs of various users.

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.

Indicators

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.