MEP Engineering Blog

What is Retro-Commissioning?

Posted by Peter Basso Associates, Inc.

Apr 17, 2015 1:19:00 PM

Retro-commissioning

Retro‐commissioning is a systematic process for investigating, analyzing and optimizing an existing building’s systems’ performance through operational and maintenance improvement measures, and helps to confirm their continued performance over time. The process assists in making the building’s systems interact to meet the Owner’s current facility requirements. This is achieved by beginning with reviewing as‐built documents and conditions to identify how the systems are to work together compared with the actual system operation, and to make recommendations where necessary to meet the Owner’s needs and improve system operation and efficiency. A Deficiency Summary is generated and a prioritization of the corrective actions is reviewed with the Owner.

A Lawrence Berkley National Laboratories Study of 60 Buildings of Different Types Showed That:

  • Over 50% had control problems
  • 40% had HVAC equipment problems
  • 15% had missing equipment
  • 25% had BAS with economizers, VDS, and advanced applications that were simply not operating correctly.

Benefits of Retro-Commissioning

Following are some of the key benefits to be realized through retro-commissioning:

  • Improved occupant comfort and productivity.
  • Improved Building Operation.
  • Improved Building Systems Efficiency and Extended Equipment Useful Life
  • Documented Building Condition and Deficiencies.
  • A List of Recommendations for Improvements.
  • A Road Map for Capital Improvements.
  • Potentially Reduced Carbon Footprint.

How Much Does Retro-Commissioning Cost?

Building type and complexity, the number of building systems, and the level of control and monitoring are all considerations in determining the cost of retro-commissioning. Here, square foot cost comparisons are not applicable. To demonstrate, following are some sample building types, square footage, retro-commissioning costs per square foot and energy savings per square foot. 

Building Type

Building Sq. Ft.

Cost/Sq. Ft. to RCx

Energy Savings/Sq. Ft.

University Library

290,000

$0.10

$1.06

University Classroom Building

92,000

$0.28

$2.03

University Lab Building

64,700

$0.28

$0.95

University Lab Building

269,100

$0.17

$0.80

Elementary School

27,000

$0.72

$0.78

High School

145,000

$0.23

$0.51

Generally the cost to retro-commission is less than the money saved by eliminating the wasted energy within a facility.  The cost to retro-commission is directly proportionate to the complexity and number of systems serving that facility.

How Do I Know if My Building is a Good Candidate for Retro-Commissioning?

If your building meets any of the following criteria, you will realize a benefit from applying the retro-commissioning process:

  • The building was not previously commissioned or re-commissioned.
  • There are building systems that seem to have never worked correctly.
  • The building has been renovated or has been expanded.
  • How the building is used has changed.
  • Operating costs have increased rapidly or beyond the rate of energy costs.
  • Occupant complaints (too hot or too cold) have increased.

Commissioning and retro-commissioning processes can help verify that all of your building’s systems and processes are functioning as designed. Get your free copy of our Building Commissioning Playbook to see how learn more about the benefits of commissioning your building.

Building Commissioning Download

Topics: Commissioning, Retro-commissioning

   

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