Diffusion theory, developed and popularized within communication research by Everett Rogers, is a venerable approach with much to recommend it as a theoretical foundation for applied communication research. In developing an applied project for a home energy conservation (energy efficiency retrofit) program in the state of Nevada, we utilized key concepts from diffusion theory but also confronted its limitations. Ultimately, in this project, the diffusion of home energy conservation to individual households depended primarily not on general adoption propensity, a personality characteristic postulated by diffusion theory, or even on financial (cost-benefit) considerations, but on an environmental orientation. This result suggests revision to the diffusion of innovations idea may be needed.