This study empirically estimated disaggregate market transaction costs facing single-family house-owners when energy renovating their dwelling. Two types of energy renovations are analysed: heat insulation and energy-saving windows. An analytical framework was developed including an adjustment mechanism for time-biases displayed by households. The decision process was modelling in three steps where households can be either latent, potential or actual clients to an energy renovation project. Data was collected by web-based surveys. The transaction costs are estimated based on time assessment, income levels and monetary expenditures occurring in the decision process. The results suggest that the magnitude of the transaction costs can be an important barrier to energy renovations. For energy-saving windows, transaction costs can constitute more than 50% of the investment cost, and almost 24% for heat insulation. The largest potential reduction in the transaction costs is found in the implementation phase.