The heating surface is the most important technical parameter of a shaft heater. Analysis of the heating value of this surface is made on a large material of projects of mine calorifier plants of various institutes of giproshaht (Mosbaosgiproshaht, Lengiproshaht, Donetskgiproshaht, Uralgiproshaht, etc.). A specific criterion of comparison, taking into account the numerous factors of influence on the size of the required heating surface, it is advisable to consider the technical indicator of mine calorifier plants. Let's call it specific heating surface, i.e. the number of square meters of the heating surface of the mine calorifier plant, coming to every 1000 kcal of heat transferred to the air per hour.