PACE has been delivering weatherization and energy-efficiency services to low-income households in Los Angeles County since 1981. The mission of the Weatherization program is to reduce energy costs for low-income families, particularly for the elderly, people with disabilities, and children, by improving the energy efficiency of their homes while ensuring their health and safety.

In the Weatherization Assistance Program, weatherization services are cost-effective energy efficiency measures for existing residential and multifamily housing with low-income residents. Under this definition, it includes a wide variety of energy efficiency measures that encompass the building envelope, its heating and cooling systems, its electrical system, and electricity consuming appliances. In other words, the full range of energy efficiency measures in buildings that apply to all homes and apartment buildings is included in weatherization technologies.

On the other hand, the Weatherization Assistance Program serves low-income families free of charge and limits according to federal rules the amount of money that can be spent on any single residence. (The average expenditure is $6,500.) As a result, only the most cost-effective measures are included in the upgrade of a particular home. This constant pressure for low-cost energy savings has become the trademark of weatherization and distinguishes it from the larger home retrofit industry.

Another distinguishing feature of weatherization is attention to all-around safety check. Many buildings receiving attention are old and in need of repair. Weatherization service providers check major energy systems to ensure occupant safety. 

The Weatherization Program is funded in whole or in part by the American Recovery and Reinvestment act of 2009 in cooperation with the California Department of Community Services and Development.