Tier 1 vs Tier 2 Metrics in Commercial BuildingApril 20, 2016
A key component to any energy efficiency project is the ability to measure the building's performance throughout its lifetime, from design through to ongoing operation. Without accurate metrics, it would be impossible to calculate existing energy costs, forecast future loads or create goals and plans for reducing consumption.
While performance data is indeed crucial, not everyone working on a given project requires the same level of detail. For example, researchers or operators might need up-to-the-minute feedback on energy system performance, while building owners or energy suppliers may simply be interested in daily or monthly consumption summaries. Therefore, processes and projects that are used to collect data are divided into two levels, or tiers, that describe the granularity of the data they collect as well as the effort it takes to gather and use said data.
Tier 1 Metrics
Tier 1 analysis offers the most high-level data. Metrics available at this tier are collected by basic processes, and are typically used to derive relatively rudimentary results, often on a monthly and annual basis. Examples include, annual purchased energy, electrical demand, and facility energy production.
One of the most defining characteristics of Tier 1 metrics is that they can usually be collected using existing data, such as utility bills, a walk-through of the building or building drawings, and do not require any additional metering equipment. This makes Tier 1 metrics relatively inexpensive and quick to determine.
Tier 2 Metrics
Tier 2 metrics yield more detailed results, but require a more advanced process to reach them. Tier 2 analysis can provide insight at more specific intervals, such as seasonally, daily, hourly, or even subhourly. It can also be sorted by the type of end use, giving analysts better insight into the type of demand at any given moment. For example, Tier 2 analysis may be necessary to calculate end-use energy totals or cost savings predictions.
To collect the necessary data, energy professionals typically use submetering or data acquisition systems to perform Tier 2 analysis. Because of the additional technical requirements, building contractors often partner with energy consulting companies for assistance in designing and implementing Tier 2 metrics programs.