All forms of building commissioning share the same goals: to produce a building that meets the needs of its owner and occupants; operates as efficiently as possible; provides a safe, comfortable work environment; and is operated and maintained by a well-trained staff or service contractor. Retro-commissioning (RCx) is the application of the commissioning process to existing buildings; typically focusing on low cost improvements to existing equipment and systems to improve their performance and operational efficiency.
For owners, RCx reduces building operating costs that can lead to an increase in net operating income. Building managers notice fewer occupant complaints and an increased ability to manage systems. Benefits resulting from RCx include improved system operation beyond preventive maintenance, improved equipment performance, increased operations and maintenance staff capabilities and expertise, increased asset value, energy savings, improved occupant comfort, improved indoor environmental quality and improved building documentation.
RCx can produce significant cost savings in existing buildings. Savings vary depending on the building type, its location and the scope of the retro-commissioning process. A comprehensive study (1) found that average energy cost savings because of RCx range between $0.11 and $0.72 per square foot and nonenergy cost savings between $0.10 and $0.45 per square foot.
The cost of the retro-commissioning process often is difficult to estimate and may vary depending on market conditions. The scope of work, the size and age of the building and the complexity of the building systems are some factors that can affect the project costs. The total RCx cost can range between $0.13 and $0.45 per square foot with a simple payback time of 0.2 to 2.1 years.
Portland Energy Conservation Inc., in collaboration with the U.S. Environmental Protection Agency, has developed “A Retrocommissioning Guide for Building Owners” that illustrates how building owners and managers can successfully use RCx as a cost-effective method to reduce expenses and increase revenue through improved building operations. The more an owner is involved in the RCx process, the lower the costs, the larger the benefits and the longer the impact.
For more information about Hanson’s retro-commissioning services, contact Jean Dussault at jdussault@hanson-inc.com or Robert Knoedler at rknoedler@hanson-inc.com.
1 Mills, E., H. Friedman, T. Powell, N. Bourassa, D. Claridge, T. Haasl, and M.A. Piette. 2004. “The Cost-Effectiveness of Commercial-Buildings Commissioning,” Lawrence Berkeley National Laboratory.