This thesis presents a comprehensive, whole-system energy analysis of ÉcoTerra using measured data. ÉcoTerra is a low-energy, near net-zero energy, solar house. It was constructed as part of the Canada Mortgage and Housing Corporation's EQuilibrium™ Sustainable Housing Demonstration Initiative, and incorporates a building-integrated photovoltaic/thermal roof coupled with a ventilated concrete slab. The roof collects thermal energy and generates electrical energy simultaneously. The thermal energy is collection is achieved by passing air under the surface of the roof and ducting this air into the house. This thermal energy is used to preheat domestic hot water, actively heat the ventilated concrete slab, and for drying clothes. The energy stored in the slab is released passively into the space. The overall energy use and end-use breakdown of the house are analyzed and discussed. The house's control system is documented, as are the changes that were made to the controls since construction. The main contributions of this work include a comprehensive energy analysis of the house and the identification of important conclusions and lessons learned. Recommendations are also made as to how ÉcoTerra, and future low-energy homes, could reach net-zero energy consumption. Large amounts of high quality data have been collected since the construction of the house, and significant effort was made, as part of this work, to structure and organize the data into usable forms for future research.