If you aren’t measuring energy consumption, you aren’t managing it. Most FMs don’t need to learn that fact. But how exactly to measure it and what metrics to use?
The ongoing tactic and long-term strategy must involve performance tracking. The rub is that building automation systems (BAS) can generate such deep and fast-moving rivers of data that it is hard for operators to pan the gold nuggets that lead to profitable outcomes. It can also be so time consuming that few can stick to it.
The solution is to track key metrics, not data points. A metric merges data from multiple points into a measurement that provides ready-to-act-on insight. Older automation systems may not offer slick dashboards, but operators can still create and display data to glean money-saving information.
Two Methods for Tracking Metrics
In its Building Performance Tracking Handbook: Continuous Improvement for Every Building, the California Energy Commission (CEC) supplies an example of the difference between data and metrics.
While collecting data on indoor zone temperatures provides useful information, over time the size of the data becomes immense. Instead, an operator can create a metric that tracks the percent of time when zones maintain their temperature setpoints. At a glance, this metric displays the key information.
Ideally each metric should have a target associated with it. If questions and anomalies arise, operators can drill down into the data as necessary.
A BAS can be used to track metrics in two complementary ways:
- Charts or plots that display patterns over days, weeks, months and years
- Values (averages, minimum/maximums and percentages)
With such patterns displayed, operators can get an instinctive feeling for how changing occupancy, weather and other variables affect HVAC efficiency.
The most common energy metrics are cost or energy units per square foot per year. Most do not have hard values or limits, which is to say that operators learn over time how their buildings perform.
For more information, download The Building Performance Tracking Handbook at the CEC’s website (www.cacx.org).
