Retro-commissioning is quite similar procedurally to standard commissioning, while being quite different for the client. Like building commissioning, retro-commissioning takes a broad look at the interactions between the many systems in a building and seeks to optimize them in relation to each other for the best possible interior conditions. What can be very different for the client is the price: retro-commissioning is performed on buildings with systems that have already been constructed, and oftentimes very cheap and simple tweaks can produce incredible leaps in efficiency.“The kinds of problems that retro-commissioning will identify and fix include: equipment or lighting that is on when it may not need to be…air balancing systems that are less than optimal…[and] controls sequences that are functioning incorrectly.”1 From this description, we can begin to see why many of these changes can be surprisingly cheap. Reprogramming controls sequences does take a skilled technician, but it also doesn’t require the purchase of replacement parts or the redesign of entire systems, which can get expensive quickly.
How can you know if your building would be a good candidate for retro-commissioning? Well, a good first indicator is that something has changed lately. Perhaps your energy bill is steadily rising, and user behaviors have been ruled out, so you suspect it’s your building itself that is no longer performing as intended. Or perhaps your building has recently undergone a use shift, such as a re-zoning from industrial to commercial. Perhaps your building is now home to more users than it was originally designed for. In times of change such as this, it can be difficult to shift the focus back to the underlying systems that often feel invisible when functioning correctly. However, a well-timed building retro-commissioning can open the door to recurring savings that really start to add up. Much like energy auditing, retro-commissioning is cost-aware. The deliverable is often a ranked list of proposed modifications, ranging from least to most cost effective. While ideally a client could make all suggested adjustments simultaneously and reap the maximum cost savings, the reality of business finance makes it a wiser choice to prioritize. This allows the client to perform their own cost-benefit analyses based on liquid capital versus desired recurring savings and environmental benefits.
One of the largest barriers to successful retro-commissioning is persistence1. Accidents like software resetting or the continual user override of control systems can have a deleterious effect on the energy savings that this service provides. This is the flip-side to the fact that many of the upgrades can be small, cost-effective parameter tweaks; the parameters can be reset again poorly if persistence is not highlighted. Ways to increase the persistence of the retro-commission benefits include employee briefings and clear signage. If the building administrator is committed to sustaining these changes because of the cost savings they provide, retro-commissioning can be a secret weapon in the fight against monthly cost bloat. If increasing your building’s performance can be as simple as a few adjustments, why not give it a try?