About the Impact Report

Letter From Our Organizations

Energy efficiency is a powerful tool that has delivered greater economic growth, reduced emissions, and enhanced our quality of life on a massive scale.

Our three institutions have been working for several decades to understand and communicate this story. Collectively we have formed numerous coalitions and partnerships, drafted leading reports and analyses, and worked to measure, map, and advocate for the use of energy efficiency to its full potential.

Energy efficiency is, by nature, diverse, with applications that reflect every aspect of energy use in every sector. In part due to this diversity — energy efficiency is more than one technology, industry, or practice — there has never been a single, one-stop report that summarizes the contribution of energy efficiency to our society. Until now.

This report seeks to tell that story, in a quantitative assessment that is nonetheless accessible and informative for energy efficiency experts and newcomers alike.

This is not an academic exercise. We have an urgent need to scale up our commitment and deployment of energy efficiency, which will be a powerful tool in our toolkit to address the need to accelerate our response to climate change, to create greater economic productivity, and to ensure affordable and accessible energy with greater resilience. Decades of experience have taught us that energy efficiency doesn’t always happen on its own: it requires proactive support among diverse stakeholders to see its benefits and work together to realize them.

And today – as before – energy efficiency is not standing still. New innovations and business models are emerging that will bring new opportunities, and change the way we deploy energy efficiency, embedding it increasingly into the connective tissue that holds our energy markets together. But understanding the trajectory that brought our market to its state today is critical to shape its future.

We are grateful for the support and thoughtful feedback provided by the contributors to the report, listed on the following pages. Without their thoughtful advice, careful review of the document, and financial support, as well as their sustained commitment to advancing effective energy efficiency deployment, this work, and our advances over the previous decades, would not have been possible.

Clay Nesler, President, Alliance to Save Energy

Lisa Jacobson, President, Business Council for Sustainable Energy

Steve Nadel, Executive Director, American Council for an Energy-Efficient Economy

Staff Contributors

Natasha Vidangos, Ph.D., Vice President for Research & Analysis, Alliance to Save Energy
Mikelann Scerbo, Senior Associate, Alliance to Save Energy

Steve Nadel, Executive Director, ACEEE
Lowell Ungar, Ph.D., Senior Policy Advisor, ACEEE
Emma Cooper, Research Analyst, ACEEE


The work described in this report was supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE EERE) under Lawrence Berkeley National Laboratory Contract No. AGZ-9-92262-01.

The Alliance to Save Energy, American Council for an Energy-Efficient Economy (ACEEE), and Business Council for Sustainable Energy (BCSE) would like to sincerely thank the following individuals and institutions for their financial support and thoughtful feedback in the development of this report:

  • Andrew Grassell and Steve Wright, Chelan Public Utility District
  • Patricia Stanton, E4TheFuture
  • Christopher Plecs, Eversource Energy
  • Jeffrey Eckel and Gil Jenkins, Hannon Armstrong
  • Roger Flanagan and Angela Gordon, Lockheed Martin
  • Gil Quiniones and Amber Sisson, New York Power Authority
  • Curt Rich and Patrick Kiker, North American Insulation Manufacturers Association
  • Joe Bryson and Jean Lupinacci, U.S. Environmental Protection Agency
  • David Nemtzow and Michael Reiner, U.S. Department of Energy
  • John Mayernik, National Renewable Energy Laboratory
  • Darren Hanway, SoCalGas
  • Aline Althen, Elizabeth Beardsley, Taryn Holowka, Marisa Long, and Sarah Stanley of the U.S. Green Building Council
  • Support was also provided by National Grid, and a number of other Massachusetts utilities (Berkshire Gas, CLC, CMA, Liberty Utilities, Unitil Gas and Unitil Electric), and Johnson Controls.

We also express our appreciation for individuals who provided technical support, guidance, and original data for specific indicators, including:

  • Rohini Srivastava, Therese Langer, Neal Elliott, and Weston Berg, ACEEE
  • Joanna Mauer, Appliance Standards Awareness Project
  • Nick Nigro, Atlas Policy
  • Ethan Zindler, Bloomberg New Energy Finance
  • Alex Kragie, Coalition for Green Capital
  • Nic Lutsey, International Council on Clean Transportation
  • Meegan Kelly, ICF
  • Peter Therkelsen, Charles Goldman, and Lisa Schwartz, Lawrence Berkeley National Laboratory
  • Casey Talon, Navigant Research
  • Janet Joseph and Vanessa Ulmer, New York State Energy Research and Development Authority
  • Steve Baden, Residential Energy Services Network
  • Robert (Bruce) Lung and Paul Scheihing, U.S. Department of Energy
  • Perry Lindstrom, U.S. Energy Information Administration
  • Beth Conlin, Stacy Glatting, Katy Hatcher, Jonathan Passe, and Emma Zinsmeister, U.S. Environmental Protection Agency
  • Bryan Howard and Maren Taylor, U.S. Green Building Council

A Comment on Report Methodology

Energy efficiency technologies span a variety of sectors, and data collections can vary in frequency, detail, completeness, and collection methodology. In some cases, different data collection approaches by different entities lead to alternative conclusions; in these cases, this report attempts to focus on those insights that can be presented with confidence, and footnote other considerations for the reader’s awareness. In other areas, the most recent available data are several years old, sometimes dating back to 2014. These older data sources were included where alternatives were not available, to complete the picture of energy efficiency’s trajectory and impacts. However, both issues – conclusiveness and regularity of collection — demonstrate an important knowledge gap that can undermine society’s understanding of energy efficiency’s impacts. Moving forward, filling such knowledge gaps will be paramount.