In Sweden, considerable energy efficiency and greenhouse gas mitigation could be achieved through the conversion of 500,000 detached houses from electricity-based heating systems to district heating, heat pumps or pellet boiler systems. House owners are central in the diffusion of innovative heating systems as they make the adoption decision. Hence, we carried out an empirical analysis of the factors affecting house owners' decisions to adopt a heating system. In June 2005 we sent out questionnaires to about 700 Swedish house owners residing in the city of