Due to desirable emission reductions and population growth, an increasing energy demand isidentified as a dire issue for energy systems. The introduction of low energy building districtsenables an increased energy system efficiency. This study’s aim is twofold. Firstly, an extensive urban building energy model is used to simulatethe yearly use and geographic distribution of the heat demand for residential and commercialbuildings that are to be supplied by a low-temperature district heating system. Two buildingenergy performance cases are studied; one where all buildings are assumed to be of PassiveHouse standard, and one where the building energy performance is in line with conventionalnew-building regulations in Sweden. The study showed that that Passive Houses will generatethe lowest yearly heat demand and that implementation of ventilation heat recovery has a bigimpact. Furthermore, the results showed that a variation of building energy performance mightbe advantageous when planning a new city district with district heating. Secondly, one specific building is in detail modeled as Passive House and according to BBR-standards and simulated in the building energy simulation software IDA ICE to investigate whatbuilding heating system is best suited for low-temperature heat supply. The temperaturedemands for floor heating and low tempered radiators is investigated and compared toconventional water-based radiators. Results showed that floor heating requires lowertemperature’s than low temperature radiators, but both are well suited for low temperaturedistrict heating. The study’s results will be used as an example for future city district planning aswell as presenting relevant heating systems for low-temperature district heating.