What is Retro-commissioning (RCx) and When Do You Need It?

What is Retro-commissioning (RCx) and When Do You Need It?


Blower testing on a window.

Building Enclosure Commissioning often comes to mind with new construction—things like air barrier, water penetration and thermal testing to ensure that a building is energy efficient and safe for its occupants. However, commissioning is not only limited to new construction. Retro-commissioning, which is exactly as it sounds: retroactively commissioning a building that has never before been through a commissioning procedure. Retro-commissioning is a process that ensures a building’s systems are running at optimal performance. Throughout a building’s lifecycle, systems age or occupants can change how a space is utilized, which can lead to potential problems that were previously unforeseen.

What is Retro-commissioning?

Retro-commissioning (RCx) is a systematic process of evaluation, testing and analysis to determine a building’s performance and identify operational improvements. According to EnergyStar.gov, it is the first stage in the building upgrade process. When many older buildings were constructed, the concept of energy efficiency was not a primary concern. Systems that were installed 20, 30 and 50 years ago may have been new at the time but may no longer be operating to today’s standards of performance and efficiency. This is where the comprehensive testing of the building’s systems in order to find deficiencies and improve outcomes comes into play.

Both commissioning and retro-commissioning tests can be performed on a building’s envelope to determine the structure’s energy efficiency. The building envelope is the surrounding structure of a building that protects both the building and its occupants from the outside environment. This can include the roof, walls, curtain wall, windows and other fenestrations.

Standardized tests that can be performed on the building envelope to identify potential sources of leaks, inadequate performance or construction errors can include:

Air Infiltration Tests

  • ASTM E779
  • ASTM E783
  • ASTM E1186
  • ASTM E1827
  • ASTM E2357

Roof Tests

  • ASTM C1153
  • ASTM D7877
  • ASTM D8231
  • ASTM E907

Water Penetration Tests

  • ASTM D5957
  • ASTM E1105
  • AAMA 501.1
  • AAMA 501.2
  • AAMA 502/503

Durability Tests

  • ASTM C794
  • ASTM C1060
  • ASTM C1193
  • ASTM D4541

When to use Retro-commissioning

A study conducted in 2004 concluded that retro-commissioning is “one of the most effective means of improving energy efficiency in commercial buildings.” Therefore, retro-commissioning should occur as a regular part of your preventative maintenance. Doing so establishes a baseline for your building’s energy performance and can help you find potential savings opportunities. Unexpected equipment or building enclosure failures can lead to expensive, unwanted costs. Taking a proactive approach utilizing a Building Enclosure Commissioning Agent (BECxA) to routinely perform tests can aid in both better understanding and better planning for the lifecycle of your building.

With 30 years of building envelope and structural engineering consultation experience, Technical Assurance offers you a comprehensive approach to preserving the life of your most expensive assets. Our commissioning and retro-commissioning services can help you identify problem areas and improve the overall efficiency of your building. We are proud to be your partner in quality assurance.


Contact Us Today!

Technical Assurance can help you take a proactive approach to ensure optimal performance of your building envelope. Contact us today for a consultation and ensure that your investment lasts well into the future.