This study focused on investigation of non-fossil fuel heat sources to be supplied to low-energy district heating systems operating in low temperature such as 55 C and 25 C in terms of, respectively, supply and return. Vast variety of heat sources classed in categories such as fossil fuel, renewable energy, and nuclear energy was evaluated in a Canadian case study with consideration given to the regional climatic condition. Hence low-energy district heating systems were considered to be supplied from an integrated energy production together with the basis of using multi-generation in several heat sources. The aim of the study was formulated to compare different forms of heat sources in the point of the performance in energy production and of environmental damage impact within a Canadian case study. Hereby, different scenarios consisting of distinctive heat production configurations each of which was arranged with differing heat sources were investigated in different perspectives such as the performance of low-energy district heating system, exergy analysis of heat production facilities, and parametric studies in management of heat distribution.