• Mills, E. and P. Mathew. 2009. “Monitoring-Based Commissioning: Benchmarking Analysis of 24 UC/CSU/IOU Projects”. Lawrence Berkeley National Laboratory Report 1972E [Full Report: [PDF]


This report documents an in-depth benchmarking analysis of energy savings from a portfolio of 24 Monitoring-based Commissioning (MBCx) projects designed to achieve energy and peak power savings in the University of California and California State University system buildings. In the course of the analysis, we developed a quality-control/quality-assurance process for gathering and evaluating raw data from project sites and then selected a number of metrics to use for project benchmarking and evaluation, including appropriate normalizations for weather and climate, accounting for variations in central plant performance, and consideration of differences in building types. We performed a cost-benefit analysis of the resulting dataset, and provided comparisons to projects from a larger commissioning “Meta-analysis” database.

In the course of commissioning the projects described in this report, we identified a total of 1120 deficiency-intervention combinations. The most common location of deficiencies was in HVAC equipment (65% of sites), followed by air-handling and distributions systems (59%), cooling plant (29%), heating plants (24%), and terminal units (24%). From these interventions flowed significant and highly cost-effective energy savings For the MBCx cohort, source energy savings of 22 kBTU/sf-year (10%) were achieved, with a range of 2% to 25%. Median electricity savings were 1.9 kWh/sf-year (9%), with a range of 1% to 17%. Peak electrical demand savings were 0.2 W/sf-year (4%), with a range of 3% to 11%.

The aggregate commissioning cost for the 24 projects was $2.9 million. We observed a range of normalized costs from $0.37/sf to 1.62/sf, with a median value of $1.00/sf for buildings that implemented MBCx projects. Half of the projects were in buildings containing complex and energy-intensive laboratory space, with higher associated costs.

A median simple payback time of 2.5 years was achieved for the portfolio.

The greatest absolute energy savings and shortest payback times were achieved in laboratory-type facilities. While impacts varied from project to project, on a portfolio basis we find MBCx to be a highly cost-effective means of obtaining significant program-level energy savings across a variety of building types. Energy savings are expected to be more robust and persistent for MBCx projects than for conventionally commissioned ones.

The project was sponsored by the buildings- and industrial-sector units of the California Energy Commission's Public Interest Research (PIER) Program.