Building performance standards (BPS) are changing the conversation about existing buildings. Instead of focusing only on the equipment a building has, owners must pay attention to how much energy it uses and whether its performance improves over time. For many facilities, the first step is to understand why actual operation differs from the original design or current expectations.

Retrocommissioning provides a structured way to find out. It evaluates existing systems, identifies operational problems, and verifies whether corrective actions improve performance. EEI’s Scott Usselman recently discussed this approach in an SBX Plus presentation hosted by the Smart Buildings Center and Northwest Energy Efficiency Council.

Look Beyond the Utility Bill

Utility data can show that a building uses more energy than expected, but it rarely explains why. A retrocommissioning team combines that data with building automation system trends, equipment information, field observations, and functional testing. The goal is to understand what systems are doing during occupied and unoccupied hours, including how they respond to changing loads and outdoor conditions.

Common findings include HVAC equipment running longer than necessary, sensors that report inaccurate conditions, control overrides that remain in place, and heating and cooling operating at the same time. Each issue can increase energy use without being obvious to occupants or operators. Retrocommissioning also examines ventilation, equipment staging, temperature resets, and air and water distribution to identify opportunities that fit the building’s actual use.

Turn Findings into Verified Improvements

An effective process starts with a baseline of energy use and operating conditions. The team documents deficiencies, recommends corrective actions, and works with building staff to prioritize them. Some measures involve maintenance or controls adjustments; others require repairs or capital planning. The right sequence depends on the building, its systems, and the applicable performance target.

Implementation is followed by verification. Did the schedule change reduce unnecessary runtime? Are the controls now maintaining the intended conditions? Do post-implementation trends and energy data support the expected result? Tracking these answers helps owners distinguish a completed task from a demonstrated performance improvement.

Documentation matters, too. A clear record of the original condition, action taken, and measured outcome gives facility teams a basis for ongoing operation. It can also support the reporting and planning needed for BPS compliance, subject to the specific requirements of the jurisdiction and program. Retrocommissioning alone does not guarantee that a building will meet its target, particularly when larger equipment or envelope upgrades are needed.

Build on the Work

The greatest value comes when retro commissioning is treated as the start of a continuing performance effort. Building operators can use trends, alarms, and periodic reviews to catch drift before it becomes another year of excess energy use. Owners gain a clearer view of which improvements can be made through operations and which belong in a longer-term capital plan. For buildings facing performance requirements, that is a practical place to begin: understand current operation, fix what is within reach, verify the results, and use the evidence to plan the next step.