The ways of energy saving in air heating of cabins of mobile machinery (tractors, trucks, harvesters) and production facilities are discussed. It is shown that in the cabins of mobile machines with a relatively small volume with no exhaust ventilation to reduce energy consumption for heating, while regulating temperature at workplace and relative humidity, is to use partial recirculation of treated air. Specific recommendations for the heating of the mobile machine cabins, which is characterized by basic parameters such as thermal performance, air flow and temperature are given. It was found that the partial recirculation of the treated air in the cabin of the mobile machine has allowed to reduce energy consumption for heating in 1.94 times and provided on working place of operator normalizable relative humidity without any additional units for humidification. It is shown that in areas of larger volume, where maintenance and repair is carried out in the presence of local exhaust ventilation, standard for relative humidity could be provided only with humidifier. Thus in order to reduce energy consumption for heating it is necessary to dispose the exhaust air heat flow to preheat the incoming air using the heat exchanger-recuperator provided with an exhaust air dryer to avoid freezing of apparatus at low ambient temperature conditions. The filler of drying unit could be silica gel as water absorption by silica gel is accompanied by increasing treated air temperature and in the heating system it leads to energy consumption and is a positive characteristic.