From air sealing to improving ventilation to adding insulation, home weatherization helps consumers save money by saving energy. This month marks the 40th anniversary of the Energy Department's Weatherization Assistance Program (WAP), which provides funding to states, territories, and tribal governments to improve the energy efficiency of the homes of low-income families, persons with disabilities, and senior citizens. Thanks to its enduring spirit of innovation, WAP has accomplished the weatherization of more than 7 million American homes.

WAP was born out of the 1973 oil crisis, when unemployment and energy prices were exceptionally high. Energy conservation measures emerged as one of the nation’s top priorities. In 1976, Congress passed the Energy Conservation Policy Act and WAP became an official program.

The first decade of WAP saw weatherization crews focus on fundamentals of air sealing: installing cellulose insulation and caulking. As the program’s expanded its services through the 1980s and 1990s, so did understanding of the building as an entire system. New testing technologies such as infrared cameras and blower doors allowed auditors to see into homes in a new way.

Weatherization technicians recognized that a building’s shell, appliances, and its occupants all affected the safety and comfort of a home. This concept became known as the “whole-house” approach, and weatherization and home performance technicians use this approach today to ensure that all parts of the home work together to maximize efficiency, comfort, and health.

WAP has evolved to become one of the most successful programs in the federal government for advancing an energy-efficient  economy. The program performs energy audits on each home to determine which measures are most cost-effective, and every dollar spent on weatherization improvements can return $1.53 in energy savings over the life of the measures.

WAP also serves as a job multiplier because of its ability to leverage Energy Department funding, combined with other federal, state, utility, and private resources, to increase the number of homes that can be weatherized in a region and provide additional weatherization services.

The Weatherization Training Centers (WTCs) lead the nation in implementing the resources created under the Guidelines for Home Energy Professionals project. These specialized training organizations teach whole-house building science to weatherization workers who are able to immediately put these valuable skills into practice. Throughout the country, these institutions provide several methods-driven courses to weatherization professionals.

Today, WAP is building on its legacy of technological and workforce innovation with new initiatives, including the Home Energy Professional program, which provides professional certifications to skilled workers; the Standard Work Specifications which ensure that weatherization and home performance work is done to the highest standard; and the Healthy Homes Initiative, which emphasizes the importance of indoor air quality when retrofitting homes.