Concepts for a dual use of "micro-combined heat and power units" (CHP) in vehicles and buildings can also be designated as "micro-power conditioning units" (PCU). In electric vehicles (EV), the thermal conditioning of the battery pack needs special attention. In an ongoing research project, micro-PCU concepts with a mechanical power in the range of 1 to 15 kW are investigated. A PCU integrated in a vehicle is not in use during parking periods, therefore a mobile integration and additional application of the PCU in adjacent fields could increase the overall sustainability in energy utilization. It is intended to transfer the CO2-reduction potential of a battery electric vehicle (BEV) to the owner's house in order to increase the acceptance of BEVs. To introduce the dual use of PCUs in housings, it is necessary to characterize the typology of buildings and the respective standards of heat insulation, as well as the common energy requirements. Additionally, it is calculated, whether the use of PCUs in residential buildings could decrease its CO2-emissions. In Germany, 42% of residential buildings are detached houses. Using the example of a detached house, the potential application and benefits of PCUs with a mechanical power in the range of 1 to 3 kW are studied. The analysis shows that the use of fuel-operated PCUs in a single-family house may result in 14% reduction of the total CO2-emissions. Without major modifications, conventional fuel-operated engines could also be run by the use of liquefied petroleum gas (LPG). If LPG-operated PCUs could be used in a building, the potential of CO2-reduction rises up to 35 % in comparison to a standard heating unit. However, the CO2-reduction could not be increased by enhancing the power of a PCU (4 kW) because in contrast to smaller units (2 kW) the higher thermal output of 4kW units cannot be used, and therefore the thermal efficiency is decreased. To summarize, it could be possible to reduce CO2-emission by integrating a PCU of a BEV in the buildings heat unit; however only in a narrow range of power is the implementation of PCUs of a significant benefit.