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Category: Energy Efficiency

Retro-commissioning is the process of optimizing the performance of existing buildings by fine-tuning their systems. Buildings that were not commissioned during construction, have undergone changes in use or function, or are demonstrating inefficiencies can all benefit from retro-commissioning. It is the most cost-effective way to improve energy efficiency, and can earn green building certifications for old and previously inefficient buildings. This process can be more sustainable and cost-effective than new construction because it retains the energy and materials in existing buildings. 

Retro-commissioning occurs in 4 steps:

  1. Project planning. First, a project must be identified. Prime project candidates include buildings that have inexplicably low energy performance ratings or high energy consumption, recurrent equipment or system failure, and/or frequent complaints about building comfort from occupants. Once a building project is selected, establish measurable goals for system performance and assemble the project team. 
  2. Investigation. The goal of this stage is to identify the cause of underperformance and identify potential upgrades. Examine utility bills, building design documents, and system operation manuals. Conduct functional testing of equipment and interview operational staff. 
  3. Implementation. The project team, which can consist of third-party contractors and/or highly skilled internal staff, works to execute recommended upgrades. Throughout the process, they verify the results to ensure successful improvements and establish a new performance baseline.
  4. Training and maintenance. The project team trains the operations staff on how to use, monitor, and maintain the upgraded system. They should know how to identify when the building requires another round of retro-commissioning. 

Retro-commissioning offers the opportunity for energy savings and improved efficiency. For optimal benefits, conduct retro-commissioning every 3-5 years for each building. 

Benefits of Retro-commissioning

  • Typically focuses on low-cost operation improvements rather than expensive equipment upgrades
  • Reductions in maintenance costs and extended equipment lifetime
  • Improved indoor air quality
  • Improved productivity due to improved comfort


  • Requires additional training for maintenance staff 
  • Causes temporary disruptions to building operations
  • Sometimes requires adoption of energy reduction behaviors from occupants




  • GHG Impact


    With energy reductions in the 20-30% range, CO2 reduction can be significant.


  • Economic Impact

    Net Savings

    Targets low-cost upgrades and reduces the cost of equipment maintenance and energy usage.

    Many retro-commissioning projects can be implemented during scheduled renovations. 

  • Feasibility

    Some Challenges

    Many retro-commissioning projects can be implemented during scheduled renovations. The difficulty of the project depends on the project complexity as well as the building age and condition. 

  • Timeline

    1-2 years

    Many improvements are operational and can be implemented immediately.

  • Maintenance


    Can often uncover areas where deferred maintenance has caused issue. Ongoing, it can prevent those higher deferred maintenance costs.

  • Publicity

    Under the radar

    Projects happen behind-the-scenes, creating improvements that benefits occupants and the bottom line with limited PR value.


Retro-commissioning Providers