Building Systems Operation: Are They Operating Properly?

By Rudy Holesek, Contributing Columnist

Editor’s Note — October 2026: This contributed article was originally published in 2012. The tools, benchmarking requirements, and energy-performance standards available to building owners have evolved since then, but the central operating question remains relevant: Is your building equipment simply running, or is it operating as efficiently and effectively as intended?

How is your equipment operating? Or more accurately, how are you operating your equipment?

How do you know your equipment and systems are operating properly, and what does “properly” mean? Relative term, relative to the application.

If your system was designed and installed for a specific use, you may have an easier task. Often, however, equipment was installed for a different use or perhaps for a different tenant. Maybe the previous application had a greater load, maybe less.

Maybe there have been previous energy-saving measures put in place. Those measures could include new lighting, a better-performing roof and windows, more efficient office equipment, or greater or lesser occupancy.

You can begin to determine whether equipment is operating properly by looking at how it is being used compared with its requirements.

A good example is a building that was converted from an R&D or lab environment to office space. In this case, the equipment may be oversized, and the heating and cooling requirements may be very different from those for which the original systems were designed.

The equipment may be “working properly” in the sense that it runs when called upon. It still may not be operating properly for the building’s current use.

A load analysis can help determine what the building actually requires for heating and cooling capacity. This is particularly important when contemplating replacement of HVAC equipment. The existing capacity should not automatically become the basis for the replacement system.

If you are fortunate, you may have the original specifications and performance data from the installation. That information can provide a useful starting point for evaluating system or building performance. It does not, however, tell you whether the equipment is currently being operated properly or efficiently.

Start With the Building’s Actual Performance

Today, building owners and facility managers have considerably better tools for tracking and assessing energy performance than they did when this article was first published.

ENERGY STAR Portfolio Manager remains one widely used platform for measuring and tracking building energy and water consumption. Depending on the property and jurisdiction, benchmarking may also be part of regulatory reporting requirements.

The important point is to establish a performance baseline.

Gather the information available for the building, including its size, occupancy, operating hours, major uses, energy consumption and cost data. From there, compare actual performance against appropriate benchmarks and against the building’s own historical performance.

Benchmarking does not diagnose the problem. It tells you where further investigation may be warranted.

If a building is consuming substantially more energy than comparable properties or its own operating history suggests it should, the next question is why.

Then Look at How the Systems Are Actually Operating

That is where existing-building commissioning, recommissioning or a targeted engineering assessment can become valuable.

If you have the original architectural and mechanical design documents, they provide an important reference point. If you have documented changes made over the years, even better.

Buildings rarely operate forever exactly as originally designed.

Tenants change. Occupancy changes. Hours change. Spaces are renovated. Equipment is replaced. Controls are adjusted. Temporary operating decisions sometimes become permanent without anyone intending them to.

An existing-building commissioning effort can examine how the systems are operating today and identify opportunities to improve performance.

Typical findings may include:

• Temperature sensor location or calibration problems
• Equipment schedules that no longer match actual building hours
• Temperature setpoints and setback schedules that need adjustment
• Lighting or HVAC overrides that leave systems operating unnecessarily
• Improperly adjusted or inoperative valves and damper actuators
• Economizer problems
• Chilled-water or discharge-air temperature setpoints that are no longer appropriate
• Failed or leaking steam traps
• Compressed-air leaks or improper pressure settings

Depending on the size and use of the facility, relatively modest operating corrections can produce meaningful reductions in energy use and operating cost.

The larger lesson is simple: equipment that turns on, heats, cools or moves air may still be operating inefficiently or may no longer be appropriate for the building it serves.

Before replacing equipment, adding capacity or accepting high energy consumption as normal, understand what the building actually requires and how the existing systems are performing against that requirement.

Leadership Takeaway: Before approving a major equipment replacement, ask the team to demonstrate that the existing capacity still reflects the building’s current use and load. Replacing yesterday’s system with a newer version of the same capacity can lock an old assumption into the next capital cycle.

Rudy Holesek was President of Apollo HVAC Corp. in Bay Shore, New York, and served as Chairman of the U.S. Green Building Council Long Island Chapter, Vice President of BOMA-LI, and a member of ASHRAE when this article was originally published.