September 28, 2023

Energy Codes Then and Now, 1983 – 2021

Explore the evolution of energy codes and their impact on building efficiency. Learn how energy codes have improved since 1981, enhancing safety, sustainability, and quality in construction.

What a difference a decade makes. Or in this case, three decades. Energy sources and the way we use them have changed considerably since the 1980s. Since their inception in the 1970s, energy codes have reduced a significant amount of energy (almost a third) wasted by U.S. buildings. Today’s energy codes represent a 55% improvement in energy efficiency at the national level compared to the codes in 1981.

Why are energy codes so important? Building codes address critical societal concerns, including public health, safety, and environmental protection. Together, a suite of codes play a significant role in determining a building’s quality, safety, and energy efficiency for its entire lifespan. They also impact operational and maintenance costs, and provide a universal language for architects, engineers, builders, contractors, and inspectors.

In the absence of a national energy code in the United States, states and local authorities have the option to adopt either the International Energy Conservation Code® (IECC®) or ANSI/ASHRAE/IES Standard 90.1 for regulating energy efficiency standards in construction. The IECC, part of the International Codes developed by the International Code Council, comprises administrative guidelines for adoption and enforcement along with mandatory energy conservation requirements applicable to both residential and commercial construction. Since the 1980s, when states started embracing energy codes, there has been a consistent trend of adopting updated versions of the code every three years, each iteration progressively increasing the stringency of energy efficiency standards.

The updated energy codes are significantly helping address energy issues by prioritizing efficiency in building design and construction. Communities using these updated codes benefit, and jurisdictions enforcing them enact positive change that enhances people’s lives and safety.

Check out this graphic from the International Code Council (ICC) to see how the International Energy Conservation Code has evolved from 1983 to 2021!


This material was developed by the Interstate Renewable Energy Council (IREC). It is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Award Number DE-EE0009455 (“EMPOWERED”). The views expressed herein do not necessarily represent the views of the U.S. Department of Energy or the United States Government.