Retro-commissioning and Existing Building Commissioning

March 19, 2012
Retro-commissioning can dive deep into your building’s energy profile.

Your facility might be sparkling clean with plenty of daylight and no thermal comfort complaints, but under its initial appeal, your building systems might be wasting energy – and money – with few noticeable symptoms.

Retro-commissioning (RCx), also known as existing building commissioning (EBCx), reveals where your building is using more energy than it should and provides your team with an educational opportunity.

How Does It Work?
The process is customizable to each facility’s needs, says Jonathan Bailey, senior facility assessor at the international construction consultancy Faithful+Gould.

Some customers request that the commissioning team merely deliver a list of action items the facilities staff needs to tackle, Bailey explains. Others want the team to assist the staff through the whole process, from creating a game plan for inspection to demonstrating savings to the C-suite.

“So many facility managers have these projects on a capital funding request list sent in for approval but are denied,” Bailey says. “Often when a consultant from the RCx team comes in and says ‘These are viable projects and here are the savings you can expect,’ the projects that make financial sense get bumped to the top of the list.”

The retro-commissioning process typically costs 13-45 cents per square foot with an average payback of 1.1 years, according to Amanda Potter, executive director of the California Commissioning Collaborative, a nonprofit promoting viable commissioning practices in California. Retro-commissioning includes four phases:

  1. Planning: The provider and the building owner or facilities manager meet to outline operating requirements, the scope of work expected, project goals, the schedule, commissioning team members, and deliverables, Potter explains.

  2. Investigation: The team examines your facility in detail, starting with a review of building documentation, equipment lists, O&M manuals, and other important documents – “everything they can get their hands on,” Potter says. They examine and test equipment and monitor system performance, as well as factors like whole building energy consumption and weather data, to determine if the building responds correctly to temperature changes and other influences.

    “It’s not uncommon in a large building to be heating and cooling a space at the same time,” Potter notes. “This happens when there’s a problem with the control system.”

  3. Implementation: The team delivers a master list of findings that details what issues they found, recommendations on how to fix them, and the cost of each repair. The facilities staff is free to fix the problems in-house or pay a third party to improve the building’s performance. The provider will typically verify the corrections have been implemented properly.

  4. Handoff: The provider ensures the facilities staff can maintain the improved performance with training and documentation about how the systems should operate, increasing the staff’s understanding of building systems and troubleshooting.

Where to Start

Get Ready for Retro-Commissioning

Save time by gathering essential documents before the retro-commissioning provider arrives. These might include:

  • As-built or design drawings, controls drawings, or shop drawings/submittals
  • O&M manuals
  • Building design or operation standards, including occupancy temperatures, schedules, and test and balance reports
  • 12 months of gas and electric bills
  • Contact information for third-party maintenance and service vendors, plus access to any applicable contracts and service agreements
  • Manufacturer and model of the building automation system (if applicable)
  • Five-day trending of equipment, including chillers, outside air temperature and relative humidity, cooling towers, air handlers, and other rooftop equipment
  • Sequence of operations for all equipment
  • Lighting system specifics, including lamp types and controls
  • Types of transformers

Look for abnormal energy use, an increase in work orders, or repeated tenant complaints to determine where to start. If you manage a portfolio of buildings, look for one that won’t need a renovation soon but still consumes more energy than it should.

“Focus on buildings that don’t need to be renovated or need extensive capital investment immediately, but instead are operating in a state where it’s going to be several years before that building needs to be renovated,” Bailey recommends. “Complaints and work orders are drawing your other technicians away from doing preventive maintenance work that keeps those buildings running efficiently.”

Finding and fixing hidden sources of energy waste can yield significant results, sometimes in less than a year, Bailey says. To reduce the size of your request for RCx project funding, he recommends completing one building in your portfolio at a time and reinvesting the savings into the next building. Don’t neglect maintenance and the team’s recommended O&M improvement, however. The process will provide inaccurate results if you revert to inefficient methods and don’t regularly monitor energy use and other benchmarks for changes.

“If you put performance tracking in place, it’s really helpful in making sure the building isn’t drifting off its set points,” Potter advises. “You want your facilities staff tuned in and looking for a root cause when something drifts. Call the provider instead of responding to a thermal comfort complaint by overriding the control system.”

Janelle Penny ([email protected]) is associate editor of BUILDINGS.

About the Author

Janelle Penny | Editor-in-Chief at BUILDINGS

Janelle Penny has more than a decade of experience in journalism, with a special emphasis on covering facilities management. She aims to deliver practical, actionable content for facilities professionals.

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