What is retro-commissioning?

Retro-commissioning is the application of the commissioning process to an already existing facility. The goal: To optimize building performance and increase energy efficiency given existing systems and facility usage. Today, retro-commissioning represents nearly 40% of the EEI's service activities.

Retro-commissioning is a disciplined, systematic, engineering-based approach to systems re-development, combining engineering skills and technical field services.  It is heavily controls-system orientated and includes the review of control applications, sequences of operation, testing and loop tuning.  Controls work may be supplemented with cleaning, balancing, mechanical and electrical equipment overhauls, repairs and modifications, which may be done by in-house staff or service contractors.

The Commissioning Authority (CxA) generally begins by establishing the minimum design criteria, based on the existing systems, current facility/user needs and industry benchmarks for systems performance.  The CxA then tests the existing systems and compares the results to the established design criteria to identify system deficiencies.  Once deficiencies are identified, the CxA will make recommendations for improvements and may work with the facility owner in planning, designing and implementing solutions to remedy system performance issues and increase energy efficiency and overall system performance.

How is this different from commissioning and re-commissioning?

"Commissioning" generally refers to the commissioning of new facilities. 

"Re-Commissioning" refers to the commissioning of facilities which were previously commissioned.  Re-testing the facility systems at a later date provides current system performance measurements, which are then compared to prior commissioning test results (now benchmarks).  By comparing the test results from the initial and subsequent commissioning efforts, the CxA can identify problematic areas before they turn into major system malfunctions. 

Why do facility owners/managers retro-commission their facilities?

Retro-commissioning may be used to:

  • Identify and resolve specific performance issues
  • Adapt system functions to changing building uses
  • Increase system efficiency and reduce energy consumption
  • Analyze overall system performance and identify deficiencies
  • Identify the causes/solutions for general system degradation

What are the benefits of retro-commissioning?

The many documented benefits resulting from retro-commissioning include:

  • Improved system operation
  • Improved equipment performance
  • Increased operations & maintenance staff capabilities and expertise
  • Increased asset value
  • Energy savings
  • Improved environmental control
  • Improved occupant comfort
  • Improved indoor environmental quality
  • Improved building documentation
  • Reduced operating and maintenance costs
  • Reduced maintenance/troubleshooting issues

Who benefits from retro-commissioning?

Everyone benefits from retro-commissioning. For owners, retro-commissioning reduces building operating costs, which can lead to an increase in net operating income. Building managers receive fewer occupant complaints and improved ability to manage systems.  Building operations and maintenance personnel receive system training and improved documentation, and building occupants are generally more comfortable and therefore more productive.  Additionally, with the increased application of Energy Star as a building performance metric, improved energy performance translates to a higher score and improved marketability for leased space.

What services are included in retro-commissioning?

The retro-commissioning process is customized to fit specific client goals and project details and may be directed toward specific problem areas in a facility.  The following services are available through a comprehensive retro-commissioning program:

Discovery Phase
Existing Facility Evaluation
  • Identification of facility manager goals and objectives
  • Facility walk-through
  • Existing documentation review & analysis
  • Preparation of one-line diagrams
  • System testing to establish current system performance
  • Compilation and analysis of data collected
Retro-Commissioning Plan Development
  • Systems identification
  • Equipment lists
  • Testing priorities and schedules
  • Budget
  • Test procedure development
Testing Phase
Retro-Commissioning Plan Execution
  • Equipment data collection and analysis
  • Direct Digital Control verification and calibration
  • Field testing of equipment
  • Trending
  • Metering
  • Performance testing (partial- and full-load)
  • Compilation/evaluation of collected data
  • Development and presentation of recommendations with estimated budgets and project payback
Implementation Phase
Minor Repairs/Tune-Ups
  • Replacement/installation of minor equipment
  • Controls adjustments
  • System tuning
Major Repairs/Tune-Ups
  • Development of detailed design/construction scopes of work
  • Development of detailed project budgets
  • Peer review of the design
  • Construction administration
  • Construction management (without risk)
Final Verification Phase
  • Functional testing of revitalized systems
  • Review of test results against prior measurements
  • Final report to owner

What is a Commissioning Authority?

The CxA is the firm (or the individual within the firm) hired to provide building commissioning services.  The CxA is responsible for overseeing and executing the entire commissioning process.

Ideally, the CxA should be an independent third party (separate from the design and construction teams), knowledgeable in the design, construction and operation of engineered systems.  A qualified CxA will provide added value to the project by applying systems expertise, experience and common sense to resolve system problems.

What qualifications should I look for in a Commissioning Authority?

The CxA should have extensive commissioning experience working with facility types and systems similar to those being commissioned.  The CxA should also have experience working on projects of similar size and be able to demonstrate adequate resources (staffing) to see the project through to completion.

The CxA's firm should have both registered professional engineers and controls technicians with extensive (20+ years) building systems experience.  While a number of companies have entered the commissioning arena, many provide commissioning on a "pass/fail" basis.  The true value of the CxA is not only their ability to report system failures, but to also identify problems before construction (through peer review), analyze system failures to help identify the cause, work with design/construction teams in resolving these issues, and train facility personnel on system operations and maintenance activities.  These services require professionals with extensive system design knowledge and field experience.

What funding sources should I consider for retro-commissioning?

We encourage our clients to consider the following sources for funding retro-commissioning projects:

  • Utility cost savings (rolled from one project to another)
  • Utility company incentive programs
  • Building operating budget
  • Controlled maintenance funding (retro-commissioning specific)
  • Controlled maintenance funding (project specific)
  • Capital investment
  • Building programs with a portion of the cost set aside for central plant and central systems upgrades and improvements
  • Third-party investors
  • Shared savings programs
  • Combination of the above

Can my project be funded from the projected energy savings?

Retro-commissioning may be provided on a fee-for-service or shared-savings basis.  If the facility owner cannot afford the retro-commissioning study or the implementation of its recommendations -- and the potential for energy savings is there -- EEI may offer to provide its services through a shared-savings program.  However, once clients see the savings potential, most opt to self-fund the program.


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