The air pollutant emissions of a motor vehicle do not only mean the emissions from the engine used for propelling the vehicle. Another possible source is the passenger compartment heater. In the focus of our research, we investigated the effect of mixing gasoline-powered cabin air and ethanol (E10, E30, E100 on a volumetric basis) on the emissions of the equipment. Among the pollutant components examined, there were conventional components and so called not-conventional components. The chosen length of the test was 1800 s, while the intake air parameters temperature (tin) and relative humidity (h) have been kept constant (tin = 15 °C, h = 30%). Bioethanol mixing has a significant reducing effect on NOx (oxides of nitrogen) and CO2 (carbon dioxide). As for the components CO (carbon monoxide), THC (total hydrocarbons), CH4 (methane) and N2O (nitrous oxide), the values of the components reach usable values only in the start-up and burnout phases, while in the stable-operation phase, their values are outside the limit of detectability. A small part of THC is only CH4; a more significant part is NMHC (non-methane hydrocarbons). The results of the developed vehicle fleet model for calculating the GHG (greenhouse gas) emissions of a vehicle fleet equipped with such a device showed that the fleet’s GHG emissions are less than 1% of the annual emissions from the combustion of transport fuel.