BERKELEY, Calif. - A new study on building commissioning from Lawrence Berkeley National Laboratory (LBNL) shows that the commissioning process achieves median energy savings of 16 percent for existing buildings and 13 percent for new construction. According to LBNL, the results demonstrate that commissioning is arguably the single most cost-effective strategy for reducing energy, costs, and greenhouse gas emissions in buildings today.

The study is said to encompass the largest database of commissioning case studies for new and existing buildings, representing a major update and expansion of a study initially published in 2004, with roughly three times as many projects. LBNL said this study responds to a widely held concern that end-users do not have confidence in the nature and level of energy savings that can be achieved through the commissioning process. It addresses this issue by assembling diverse case studies and previously unpublished data, and developing performance benchmarks using standardized assumptions.

Key findings are:

• Median commissioning costs: $0.30 and $1.16 per square foot for existing buildings and new construction, respectively (and 0.4 percent of total construction costs for new buildings)

• Median whole-building energy savings: 16 percent and 13 percent for existing buildings and new construction, respectively

• Median payback times: 1.1 and 4.2 years for existing buildings and new construction, respectively

• Median benefit-cost ratios: 4.5 and 1.1 for existing buildings and new construction, respectively

• Cash-on-cash returns: 91 percent and 23 percent for existing buildings and new construction, respectively

• Considerable reductions in greenhouse gas emissions were achieved, at a negative cost of -$110 and -$25/tonne CO2-equivalent.

• High-tech buildings are particularly cost effective, and saved large amounts of energy and emissions due to their energy-intensiveness.

• Projects employing a comprehensive approach to commissioning attained nearly twice the overall median level of savings, and five-times the savings of projects with a constrained approach.

• Non-energy benefits are extensive and often offset part or all of the commissioning cost.

• Uniformly applying the median whole-building energy-savings value to the stock of U.S. non-residential buildings yields an energy-savings potential of $30 billion by the year 2030, and annual greenhouse gas emissions reductions of about 340 megatons of CO2 each year.

For a copy of the complete report, go to http://cx.lbl.gov/documents/2009-assessment/LBNL-Cx-Cost-Benefit.pdf.

Publication date: 09/14/2009