Tune Up Your Building Through Retro-Commissioning

Imagine a car that was designed and built, but never road tested before being put into production. The malfunctions would be plenty, and recalls would be inevitable. Customer complaints would skyrocket, and whatever car company engaged in such a lousy business plan would soon go bankrupt. Sounds crazy right? In reality, that absurd scenario would never play out, yet that is exactly what happens every time a building is built, but not properly commissioned – a building’s equivalent of road testing and fine tuning

Even buildings that were properly commissioned need an occasional tune-up to be sure all the parts are working correctly and to prevent expensive repairs. But what do you do with a building that was never properly "road tested" or commissioned at all?  A simple tune up won’t work, and unlike a car, we can’t send it back under protection of the “lemon laws!"

The answer is what is commonly referred to as “retro-commissioning”, which is a process that addresses problems that have developed throughout the building’s life, or problems that were there from the very beginning. Many issues uncovered by the retro-commissioning process are a result of the design itself, not just the way systems were installed.  Whatever the culprit, even the smallest problems have big impact on performance. The ultimate result is uncomfortable buildings, unhappy tenants, and substantial energy and maintenance costs.

Get Your Building Running at Peak Performance
Through a simple, multi-step process, retro-commissioning provides for systematically evaluating all aspects of a building and its energy-using systems. Problems can range from simple to complicated, so it is important the team performing the retro-commissioning understands how the systems are supposed to work.

According to “A Practical Guide for Commissioning Existing Buildings,” by Haasl and Terry Sharp of Oak Ridge National Laboratory, some basic items often targeted for retro-commissioning include:

• Adjustable speed drives that may not be operating appropriately.
• Time clocks that may have been circumvented or set up improperly.
• Energy management systems that were not installed or programmed or that may have degraded.
• Equipment running more than necessary or inefficiently.
• Controls that are out of calibration or are improperly sequencing.

Entegral Solutions recently completed a $9.5 million energy efficiency project at Mercedes ISD, in which we upgraded equipment and lighting, added control systems, and other conservation measures. There were many instances, however, where equipment was relatively new and in good condition, yet comfort was lacking and energy use was high. In those cases, we used retro-commissioning to bring the systems into optimal performance, both for comfort and efficiency. The general idea is to understand how the system was designed and intended to operate, and then fix the issues preventing it from operating as intended. Sometimes, we find that the design intent is the problem, and we make adjustments or modifications to the design that will produce more optimal performance. In the end, the retro-commissioning effort alone accounted for $75,000 in annual utility cost reductions, all while making the buildings much more comfortable for students and teachers.  

Energy and Non-Energy Benefits of Retro-Commissioning

For existing commercial buildings, retro-commissioning is one of the most cost-effective means of improving energy efficiency. There are several energy and non-energy benefits resulting from retro-commissioning which include:

• Cost savings
• Energy savings
• Improved equipment performance
• Better occupant comfort and indoor air quality
• Increased O&M staff capabilities and expertise
• Increased asset value

If this wasn't enough of a case for retro-commissioning, it is reported by the U.S. Energy Information Administration that if all existing U.S. commercial buildings were retro-commissioned and all new buildings were commissioned, their collective energy bill would be reduced by $18 billion a year! Although cars are mass produced, buildings are one-of-a-kind, which makes it even more important to "kick the tires" before signing on the dotted line. Don't get stuck with a lemon!