Using observed market quantities and prices of substitutable products, a methodology is developed to estimate economic indicators of market transformation for the energy efficient lighting market. Market transformation, an energy industry term referring to the ongoing development of self-sustaining markets for energy efficient products and services, is the goal of an increasing number of publicly-funded programs. Chief among these is the U. S. EPA's Green Lights and its successor ENERGY STAR (R). Using four decades of data related to fluorescent lighting ballasts, this study isolates product price effects and thereby permits the impacts of public programs to be distinguished from the typical workings of the market. The economic indicators are further used for deriving market volume estimates that are converted to energy savings and climate protection impacts. The findings reveal that Green Lights is responsible for annual savings in 2000 of over 5.6 million metric tons of carbon.