Return on Recommissioning

It Isn’t About Age

Recommissioning sounds like a process intended for older buildings, but that isn’t necessarily the case. Ellis says the last two projects she finished in the Twin Cities were for newer public-sector buildings in Minneapolis that had not been properly commissioned when built. Both were more than 100,000 square feet. One was only a year old, the other four years old. Her recommendations teased out energy savings of 15 percent in the first year and 30 percent in the second, with many fixes that were cheap or free. Among the problems corrected: control sequences that weren’t programmed as originally designed; controls that had been overridden to operate differently than designers intended; temperature and humidity sensors that were out of calibration; and overlooked opportunities for reducing ventilation and airflow under low-load conditions.

Hewett says that the need for recommissioning in newer buildings is quite common, simply because “there are a lot of places for things to go wrong when you construct a building.” Modern HVAC systems are complex, she says, and “the general contractor doesn’t have a lot of room in the budget to make sure everything is working properly.” That’s not to mention the “time and money pressures to make trade-offs in the HVAC system so you can put marble in the lobby.” Since commissioning adds costs to the construction budget, only a small percentage of new buildings are commissioned in the first place, she says. “So it’s not  uncommon for owners to find  that a new building doesn’t work the way it’s supposed to from the very beginning.”

In selecting targets for recommissioning, the structure’s age is less a factor than “what the building is trying to accomplish” and how its uses might have changed, agrees Jay Denny, senior energy engineer for the University of Minnesota. There are about 250 buildings on the university’s Twin Cities campus, totaling some 20 million square feet—roughly the same square footage as all the commercial real estate in downtown Minneapolis, Denny says—and for the past three or four years “we have focused on recommissioning as a campus-wide approach.” Ten buildings have been recommissioned since 2004, including Moos Tower.

Projects currently underway include the Smith Hall Chemistry Building, built in 1913 and remodeled in the 1980s. “But we’re also finding significant savings,” Denny says, in a West Bank art-class building completed in 2004 and the Molecular and Cellular Biology building finished in 2002. Those three projects alone are expected to produce combined energy savings of $600,000 to $1 million per year, he says.

Even when designers and contractors do an excellent job on a new building, Denny says, “designers have to make a best guess about how the load will work. And it’s hard for contractors to anticipate things like class schedules. So contractors tend to program the system to overheat or overcool, just so they don’t make people uncomfortable to begin with.” After a few years in use, he says, better information is available about the way controls should be interlocked or sequenced, and about whether the system “needs to run for 12 hours a day or maybe only eight, and not at all on weekends.”

So if you own a white-elephant building that freezes you in winter, fries you in summer, and plagues you with crippling energy bills, don’t be too quick to assume the only answer is to hire an arsonist. Maybe the joint just needs a tune-up.