Large scale energy efficient renovation of buildings is one of the most important tools to realize the society's need of a more sustainable building stock. Most Norwegians own their own homes. Therefore private homeowners are a focus group for the government urging to accelerate the dwelling energy efficiency rates. Success factors were identified in the in-depth study of the decision process of eleven homeowners. Large differences in energy use due to the building's condition and the occupants' behavior was encountered in the sample. Only homeowners who were conscious consumers and did not trust expert advice or that had special knowledge due to their professions succeeded in realizing energy efficiency by renovation. Lack of knowledge, bad advice from craftsmen or priority to work that they can do themselves stopped other homeowners from implementing energy efficiency. Increased knowledge on all the gains from energy efficiency, the availability of attractive products and services as well as easy access to reliable advice on the better renovation solutions have a large potential to get more homeowners to make energy efficient choices in the process of renovation. Coordination of more of policy strategies including specific information and incentives are needed to facilitate this.