A comparison of building performance can be shown in many ways, said Poeling, but can be condensed down to two basic approaches: comparing the building performance against itself, and comparing the building against similar buildings. This energy use index (EUI) compares 10 similar buildings.
SAN FRANCISCO - "The approaches to retrocommissioning, or tuning up a building, are as diverse as the problems from which buildings suffer," said Tom Poeling, P.E., CEM, senior project manager for EMC Engineers Inc., Denver. "The approach may be totally different if the program goal is to obtain energy savings versus a goal of improving comfort or indoor air quality."

Retrocommissioning (RCx) is getting to be a buzzword, like "green" or LEED, he said at the National Conference on Building Commissioning session, "Tuning up the RCx Process." It's important to make sure that the owner really knows what retrocommissioning means. "Be clear that this is not an energy audit. Find out what the owner really wants."

He defined RCx as "an applied, systematic process to optimize the operation of existing building systems." The process is typically split into four main phases:

Planning - Defining the owner's objectives and gathering building system data. "The goal of this phase is to create a concise and efficient plan for executing the detailed analysis required for the next phase," said Poeling.

Investigation - Identifying opportunities to improve building operations and providing economic analysis to the owner to justify the next step - implementation.

Implementation - Put the recommendations made in prior phases into action. "The work can be done by the facility's maintenance staff, the RCx provider, or through outside contractors," said Poeling.

Verification or hand-off - Preparing documentation, verifying the results of implementation, and training facility maintenance staff.

"The owner gets hung up on first cost all the time," Poeling said.

"Although retrocommissioning has been shown historically to produce an attractive economic payback, the challenge of the process is to maximize the efforts of the implementation phase. It's often necessary to invest sufficient time and scope in the planning and investigation phases to fully understand and justify the maximum number of opportunities. But given the fixed amount of resources available, a building owner would much prefer to invest those resources in implementing solutions."

In short, "Find compelling reasons to go forward. What's valuable to the owner and what's valuable to you?"

Building consumption can also be compared to national building databases, such as Energy Star’s Portfolio Manager or the Commercial Buildings Energy Consumption Survey (CBECS), which is based on the national survey, said Poeling. This figure compares the baseline energy use index of one building against the entire CBECS database.


Poeling said EMC recently participated in a retrocommissioning program sponsored by two California utilities. The goal was to optimize mechanical systems in 11 municipal government buildings. The comprehensive scope, created by the owner, included the following phases.

Benchmarking: Obtaining and analyzing three years' worth of utility data, and comparing the results against industry benchmarks. "Benchmarking is vital if the owner's main goal during the retrocommissioning process is to produce energy savings," Poeling said.

Planning: Interviews with building mechanics, obtaining as-built information, and creating a specific plan for point-to-point testing, Testing, Adjusting, Balancing (TAB) verification, and mechanical assessments.

Prefunctional testing: "This phase actually contained two main activities, and was the most time-intensive," Poeling said. "The first activity included the field work necessary to complete point-to-point testing, airflow, and water flow measurements, and mechanical assessments. The second activity included the economic analysis and creation of cost proposals to implement recommendations."

A flowchart like this can help a retrocommissioning contractor understand “as-found” equipment operation during the prefunctional testing phase.
Functional test:This involved working with a controls contractor to define the as-found control sequence and verify controls sequences using a systematic test procedure. "You can RCx pneumatics," he said. "There are tremendous opportunities."

Final report: "This involved the revision of energy models to show the results of the implemented measures. Protocols were also created for system-level benchmarking so that the owner could monitor the energy use of their buildings and compare it to the expected optimized operation." Documentation (final reports and training manuals) were created to summarize the final results of the RCx.

The owner is looking at things above the surface, he pointed out. "With RCx, you get to the root part of the problem. The beauty part is, you get swings right out of the gate." There are significant demand savings.

Finally, keep the maintenance guy in the loop, Poeling said. "He can undo in three hours what it took you three months to fix."


Don Davenport, vice president of EMC Engineers Inc., said that when it comes to getting owners to the table, "I have to come at this from my own experience. It's challenging to convince the owner to do this without it sounding like a sales pitch."

Benefits and disadvantages of “hands-off” and “hands-on” approaches to testing the operation of mechanical system components.
There are two types of owners, Davenport said. "One has no clue. The other knows there are problems but doesn't know how to start fixing them." Performing work for free (short term) can help convince this owner of the right course, he said.

"It's hard to argue with compelling data. Sooner or later, somebody who writes checks has to approve this."

For other owners, you may need to find a way to help them fund the RCx. "Understand the financial driver."

"Most RCx programs we've been involved in are utility based," said Jonathon Soper, P.E., principal with Enovity Inc., San Francisco. "Send a really experienced person onsite to look at the facility. Figure out exactly what the savings are."

And make sure you figure out implementation costs accurately. "The owner is going to go after a budget based on your estimate."

Publication date: 06/26/2006