OverviewLearning Objectives• Explain how energy usage in buildings is measured.• Discuss the data found in the Commercial Building Energy
Consumption Survey.• Explore trends in commercial building energy use.• Illustrate the importance of proper energy benchmarking.
Energy Use in Buildings• Fuels
• Electric • kWh, kW
• Natural Gas• CCF (therms)
• Steam• kLBS
• Fuel Oil• Gal (therms)
CBECS Database• Commercial Building Energy Consumption Survey (CBECS)
• Database of energy usage• Statistics related to construction, building technologies,
energy consumption, and building characteristics• Updated every couple of years• Available in PDF and spreadsheet formats
Access It • Query Tool:
http://buildingsdatabook.eren.doe.gov/CBECS.aspx
CBECS Database• Various topics to
explore• Most familiar
with commercial sector
http://buildingsdatabook.eren.doe.gov/
CBECS Database
Acknowledgement: Terry Townsend, PE
National Trends• Which facility types are impacting the overall trend?• Where are they located?
CBECS DatabaseExample• Office• St. Louis• 100,000sf
Interpreting Results• Sample Size• Energy Use Intensity
(kBtu/sf)• Energy Cost Index
($/sf)• End-Use Distribution
End‐Use BreakdownEnd-Use Breakdown
Heating25%
Cooling9%
Ventilation8%
Water Heating1%
Lighting29%
Cooking0%
Refrigeration3%
Office Equipment
4%
Computer Use8% Misc
13%
Information SourcesCorroborate information sources for each facility
You can’t determine potential savings without knowing where it’s being spent!
Ways to Use the DataGoal - Setting• Pick a goal for your facility(ies)• Focus on end uses that use the most energy
Benchmarking• Compare your facility EUI and ECI to other similar facilities.
Reality Check on LEED Energy Models• Can help verify results.
Energy Auditing Tool• Provides clues as to biggest energy users.
Ways to Use the Data
• BD+C 2009• EAp2: Minimum Energy
Performance• EAc1: Optimize Energy
Performance• EAc2: On-Site Renewable Energy
• BD+C version 4• Integrated Process• Minimum Energy Performance• Optimize Energy Performance• Advanced Energy Metering• Renewable Energy Production
Proposed ModelBaseline
Verify LEED energy model savings
ConclusionsThings to Remember When Using the Database• At a minimum, filter by climate zone, building type, and square
footage.• More input is better BUT you may run into sample size issues.
Uses for the Database• Goal-setting• Benchmarking (initial and ongoing)• Verify energy model results• Energy auditing tool
You can’t manage what you don’t measure!• Database can give you an idea of the major end uses without
even stepping foot in the building.
ResourcesWhat is EUI?• https://www.energystar.gov/buildings/facility-owners-and-
managers/existing-buildings/use-portfolio-manager/understand-metrics/what-energy
Ways everyone can benchmark performance• https://www.energystar.gov/buildings/facility-owners-and-
managers/existing-buildings/use-portfolio-manager/interpret-your-results/ways
CBECS Query Tool• http://buildingsdatabook.eren.doe.gov/CBECS.aspx