Existing Buildings

Buildings account for nearly 40 percent of the energy consumed in the United States. Typical commercial buildings use, on average, twice the energy of efficient buildings and three to four times that of the nation's highest performing buildings. With roughly 80 billion square feet of existing commercial space in the United States alone, updating existing buildings is a critical pathway to meeting climate and energy policy goals, utility efficiency targets and real estate objectives.

Studies of Deep Energy Savings in Existing Buildings

A Search for Deep Energy Savings in Existing Buildings
This two-phase set of work was conducted as part of the Northwest Energy Efficiency Alliance (NEEA) regional Existing Building Renewal (EBR) initiative to accelerate commercial market adoption of deep, integrated energy-efficient retrofits. A Meta Report builds on phase 1 work, which developed an initial list of 50 existing building projects showing improvement of 30%+ energy savings from two or more efficiency measures in the past 10 years. Ultimately, 11 of those buildings projects were investigated further with extensive research into the “story” of the retrofit, including data on measured energy use and financial information. Read the Meta Report

Commercial Office Plug Load Savings and Assessment: Executive Summary
Developed under a Public Interest Energy Research (PIER) project in California, the study inventoried plug loads in two LEED-certified California buildings, conducted detailed metering on office equipment, and assessed the effectiveness of low- and no-cost energy reduction strategies. Read the Executive Summary

Plug Loads Guide
This Guide shows how simple changes can cut costs and save energy in offices. Learn more

Events and Resources

Summit Meetings
In October 2012 NBI hosted its second summit addressing deep savings in existing buildings. This was a follow-up to the September 2011 summit, "Deep Energy Savings in Existing Buildings". In these meetings, experts discussed how to increase energy savings as well as the value of and potential for widespread deep energy savings in existing buildings.

Other Resources

The Greenest Building: Quantifying the Environmental Value of Building Reuse
Preservation Green Lab, National Trust for Historic Preservation

Screening DSM: When the TRC Blocks Efficiency, What’s Next? (PDF, 1 M)
Philippe Dunsky and François Boulanger, Dunsky Energy Consulting, Patrick Mathot, BC Hydro (ACEEE, 2012) 

Doing Well by Doing Good: Green Office Buildings
with Piet Eichholtz and John Quigley, 2010, American Economic Review

500 Collins Street Case Study
Sustainable Victoria

The Relationship Between Corporate Sustainability and Firm Financial Performance (PDF, 4 M)
Conlon and Glavas 2012

USGBC Case Study: PNC Financial Services Group, Inc (PDF, 1 M)

Additional Suggested Reading on Deep Energy Savings in Existing Buildings

Existing Building Case Studies

NBI has developed 11 case studies of energy retrofits and renovations in existing commercial buildings that use an average of 50% less energy than the national average–-most with an energy use intensity (EUI) of less than 40 kBtus per square foot. These measured performance case studies include motivations, technologies and practices, energy performance, financial information, overall project results and quotes from owner and design teams.

Deep Energy Savings in Existing Buildings Case Studies

For more buildings that perform much better than average, visit the Getting to Zero Buildings Database.