"Retro-Commissioning (RCx)" is the application of the commissioning process to existing buildings.  Retro-commissioning is a process that seeks to improve how building equipment and systems function together.

Depending on the age of the building, retro-commissioning can often resolve problems that occurred during design or construction, or address problems that have developed throughout the building’s life.  In all, retro-commissioning improves a building’s operations and maintenance (O&M) procedures to enhance overall building performance. All forms of building commissioning share the same goals: to produce a building that meets the unique 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.

Why is retro-commissioning important?

Commercial buildings frequently undergo operational and occupancy changes that challenge the mechanical, electrical and controls systems, hindering optimal performance. Additionally, in today’s complex buildings, systems are highly interactive with sophisticated control systems that can create a trickle-down effect on building operations – small problems have big effects on performance.

Unfortunately, most buildings have never gone through any type of commissioning process, and even well-constructed buildings experience performance degradation over time. No matter how well building operators and service contractors maintain equipment, if it operates inefficiently or more often than needed, energy waste and reliability problems can occur.

What are the benefits of retro-commissioning?

Everyone benefits from retro-commissioning.  For owners, retro-commissioning reduces building operating costs that can lead to an increase in net operating income. Building managers notice fewer occupant complaints and increased ability to manage systems. Building staff receive training and improved documentation, and building occupants are more comfortable.  Cost Savings: Retro-commissioning 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 found average cost savings in the following ranges:
 

Description	Range of Values
Value of Energy Savings	$0.11 - $0.72/sqft
Value of Non-Energy Savings	$0.10 - $0.45/sqft

The many documented benefits resulting from retro-commissioning include:

• Improved system operation: beyond preventive maintenance
• Improved equipment performance
• Increased O&M Staff Capabilities and Expertise
• Increased asset value
• Energy savings
• Improved Occupant Comfort
• Improved indoor environmental quality (IEQ)
• Improved building documentation

How much does retro-commissioning cost?

The cost of a retro-commissioning process is often difficult to estimate. 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. Table 1 shows average costs in a national study of retro-commissioning projects.  The data is approximately three years old and includes 14 California projects.  A project is underway to update the study with recent data and we expect the California costs to be in the range of $0.50/sq ft.  Costs may vary depending on market condition.

How does retro-commissioning fit into the State’s overall energy efficiency effort?

Through benchmarking, we can identify buildings that exhibit inefficient operation.  Often these poor-performing buildings are the best candidates for retro-commissioning.  Additional good candidates include older buildings or facilities with large loads such as a data processing centers.  According to the technical backup for the GBI, the attainment of the 20 percent reduction goal in energy usage is broken down into two initiatives:  8 percent from retro-commissioning and 12 percent from energy retrofits.

The Retro-commissioning Process.

A well-planned and executed retro-commissioning project typically occurs in four distinct phases: Planning, Investigation, Implementation, and Hand-Off.