Existing Building Commissioning – A Low-cost Path to High Energy Savings

An energy audit is the process of reviewing all energy-consuming features of a building, classifying the end-uses of the energy consumption (HVAC, lighting, plug loads, etc.), looking for high energy end-uses and making recommendations for Energy Efficiency Measures (EEMs). Simple payback calculations are typically provided for each EEM and are prioritized to provide the building owner with direction as to which EEM’s to pursue. A typical energy audit finding might be to replace less efficient fluorescent lighting with high-efficiency LED lighting; there would be costs associated with the lighting retrofit, though those costs would be recovered by future energy savings.

Existing Building Commissioning (EBCx, sometimes referred to as “retro-commissioning”) is the formal process of evaluating existing building systems, identifying and correcting issues, implementing improvements, and optimizing and verifying system operation. Low cost/no cost issues are often resolved as they are discovered during the process.  More capital-intensive issues typically need to be reviewed, evaluated, and engineered prior to final implementation.

The goal of EBCx is often to reduce energy consumption of a facility. Other goals may include improved indoor environmental quality (and occupant comfort), increased equipment life, and enhanced operations and maintenance programs; a typical EBCx project yields a combination of all the above benefits.

An energy audit is typically a more hands-off activity, relying primarily on visual observations and a review of energy usage data.  EBCx tends to be more hands-on, to include detailed equipment assessments, functional performance testing, and system monitoring.  EBCx may include some elements of an energy audit, and like an energy audit the commissioning process also identifies EEM’s and provides simple payback calculations.

EBCx services are often requested when the performance of a building has degraded significantly, and the owner has reached their limit regarding occupant complaints and high energy costs.  EBCx is not typically considered to be an EEM in and of itself, but perhaps it should be.  Studies conducted by Lawrence Berkley Laboratories and other organizations have shown that EBCx is a very cost-effective way to lower utility consumption in a building.  Of note is the study “Building Commissioning Costs and Savings Across Three Decades and 1,500 North American Buildings” published in 2020 by Lawrence Berkeley National Laboratory. This study shows that EBCx often results in simple payback periods of less than two years (Table 1).  The study also shows that corrective actions and system improvements are often very simple (for example, schedule and setpoint modifications made up nearly half (47%) of the EBCx measures identified in the study).

 20092018All Data
Median Simple Payback1.1 years2.2 years1.7 years
Sample Size (projects)300356656
Table 1 – Comparison of EBCx project median simply payback for data collected in 2009 and 2018. Source: Building Commissioning Costs and Savings Across Three Decades and 1,500 North American Buildings, 2020, Lawrence Berkeley National Laboratory.

Figure 1 – EBCx measure types implemented through two utility programs. (n=3,695 measures from 503 projects; 2018 data set) Source: Building Commissioning Costs and Savings Across Three Decades and 1,500 North American Buildings, 2020, Lawrence Berkeley National Laboratory.

Many utility companies offer incentives to pursue EBCx services. Their primary goal is to improve energy efficiency, though they are also interested in the overall performance improvements to the building. These utility incentives can often pay for most, if not all, of the capital outlay for the EBCx services, sometimes resulting in an instant simple payback period.

So, if you are interested in saving energy and improving the quality of your building portfolio, why not begin with Existing Building Commissioning? Contact Performance Validation to find out how to get started.

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