Looks like the Smithsonian Institution has 199 boxes of Reddy Kilowatt history. Everything was donated by Xcel Energy in 2005.

Bio / His Notes:
The Reddy Kilowatt trademark was created in 1926 by Ashton B. Collins. Reddy Kilowatt, Inc. licensed the trademark promotion and identification purposes by more than 150 investor-owned electric utilities in the United States and at least 12 foreign countries. The company later changed its name to Reddy Communications, Inc. In 1998 Northern States Power Company bought Reddy Communications and its assets, later changing its name to Xcel Energy.

Scope and Content:
Records documenting the development and use of Reddy’s licensed trademark, the stick figure “Reddy Kilowatt.” The figure was used to promote electrical appliances and other consumer use of electricity, as well as to promote energy conservation during World War II. The records include historical materials about Ashton B. Collins, Reddy’s creator and founder of the company. These include letters, speeches, memoranda, photographs and scrapbooks documenting his early career in the electrical power industry. Also included are company publications, advertisements, presentation materials, reports, company histories, and promotional items including materials directed at children such as comic and coloring books. Audiovisual materials include motion picture films, audiodiscs, audiotapes, and filmstrips. The audiotapes include recorded speeches by persons such as Benjamin Hooks, Barry Commoner, and John W. Gofman.

More: Reddy Kilowatt Records, 1926-1999.