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 Östersund, whose houses were originally built with resistance heaters. The results reveal that about 84% of the respondents had no plans to install a new heating system. Economic aspects, functional reliability and indoor air quality were the important factors in respondents� choice of a heating system. A district heating system has advantages with respect to functional reliability, indoor air quality, maintenance cost, system automation and time required for collection of information. A bedrock heat pump system has advantages with respect to annual cost of heating, indoor air quality, security of fuel supply, environmental benignity and market value of the house. A pellet heating system has an advantage with respect to investment cost.