The analysis of the current regulatory documents and reference and methodological literature used in carrying out calculations related to the determination of heat emissions from people engaged in various types of work is carried out. The incomplete correspondence of the values of heat emissions to the characteristics of the severity of the work performed for various types of activities, taking into account the age of people with their physique corresponding to normal body weight, was revealed. The calculated values of the coefficient of physical activity for a conditional person, as well as the values of heat emissions of men with their division by age categories, are determined. The graphs of energy expenditure for men of different ages performing the following types of work are presented: light (Ia, Ib), moderate (IIa, IIb), heavy. The obtained values of energy consumption are compared with the data of regulatory documents and reference literature for various categories of work. The relevance and necessity of taking into account data on heat emissions from people, taking into account their age, anthropometric parameters and other conditions when designing microclimate systems, including personal and adaptive ventilation systems, is shown. The results of the study will be useful to design engineers implementing circuit solutions of microclimate systems that provide comfortable parameters of the air environment in rooms for various purposes.