Retro-commissioning is the first stage in the building upgrade process. The staged approach accounts for the interactions among all the energy flows in a building and produces a systematic method for planning upgrades that increases energy savings. When the staged approach is adopted and performed sequentially, each stage includes changes that will affect the upgrades performed in subsequent stages, thus setting up the overall process for the greatest possible energy and cost savings. In this staged approach, retro-commissioning comes first because it provides an understanding of how closely the building comes to operating as intended. It also helps to identify improper equipment performance, what equipment or systems need to be replaced, opportunities for saving energy and money, and strategies for improving performance of the various building systems.
The staged approach to building upgrades accounts for the interactions among all the energy flows in a building. Each stage includes changes that will affect the upgrades performed in subsequent stages, thus setting up the overall process for the greatest possible energy and cost savings. Retro-commissioning begins the process because it provides an understanding of how a facility is currently operating and helps to identify specific opportunities for improvement.
In California, Building and Appliance Energy Efficiency Standards have made homes and commercial buildings more efficient than those in other states and in many countries. But more than half of the state’s estimated 13 million existing buildings were constructed before the first Energy Efficiency Standards were established in 1978. As a result, commercial buildings in particular offer a large reserve of potential energy savings.
Building regulations affect existing buildings as they are remodeled or enlarged, while more efficient appliance standards cut energy use in existing buildings as well as new ones.
Here are some of the ways to make commercial buildings more energy efficiency to cut costs, improve comfort, and provide a more sustainable future. For more details go to retro-commissioning in our resources section.
Specifically, retro-commissioning is a form of commissioning. Commissioning is the process of ensuring that systems are designed, installed, functionally tested, and capable of being operated and maintained according to the owner’s operational needs. Retro-commissioning is the same systematic process applied to existing buildings that have never been commissioned to ensure that their systems can be operated and maintained according to the owner’s needs. For buildings that have already been commissioned or retro-commissioned, it is recommended that the practices of recommissioning or ongoing commissioning be applied.
Recommissioning is the term for applying the commissioning process to a building that has been commissioned previously (either during construction or as an existing building); it is normally done every three to five years to maintain top levels of building performance and/or after other stages of the upgrade process to identify new opportunities for improvement.
In ongoing commissioning, monitoring equipment is left in place to allow for ongoing diagnostics. Ongoing commissioning is effective when building staff have the time and budget not only to gather and analyze the data but also to implement the solutions that come out of the analysis.
Building owners, managers, staff, and tenants all stand to gain from the retro-commissioning process. It can lower building operating costs by reducing demand, energy consumption, and time spent by management or staff responding to complaints. It can also increase equipment life and improve tenant satisfaction by increasing the comfort and safety of occupants.
Researchers at three of the foremost building-commissioning think tanks in the U.S. Lawrence Berkeley National Laboratory, Portland Energy Conservation Inc., and the Energy Systems Laboratory at Texas A&M University—concluded in a study published in December 2004 that retro-commissioning is one of the most cost-effective means of improving energy efficiency in commercial buildings. The researchers statistically analyzed more than 224 new and existing buildings that had been commissioned, totaling over 30 million square feet (ft2) of commissioned floorspace (73 percent existing buildings and 27 percent new construction). The results revealed the most common problem areas and showed that both energy and non-energy benefits were achieved. Analysis of commissioning projects for existing buildings showed a median commissioning cost of US$0.27 per ft2, energy savings of 15 percent, and a simple payback period of 0.7 years. The most cost-effective commissioning projects are typically in energy-intensive buildings such as hospitals and laboratories, whereas the least cost-effective projects are in buildings that are small in comparison with the size of the average commercial building.