One of the key indicators that characterize efficient energy use for heating purpose is the specific value per unit area and/or volume. This paper is devoted to the study of various methods application features used to determine energy need for heating, which there are a large number [1]. Determination of energy need for heating based on experimental data has a number of approximations and inaccuracies, so it is advisable to establish the annual energy need for buildings based on the calculated approaches. Addressing these challenges requires the use of calculation methods and mathematical models. Till the recent years, the methods for determining energy consumption and energy efficiency assessment in Ukraine took into account only annual energy consumption for heating and did not take into account the need for cooling and hot water supply [2, 3]. According to standard [2], the building energy efficiency should be determined on the basis of calculated or actual annual energy consumption for heating needs, while ensuring appropriate sanitary and hygienic norms in the building spaces.
Increasing the level of thermal resistance of the building envelope in combination with the choice of heat source is an urgent task. It is important to take into account changes in the cost of energy over time. Thermal modernization, in its turn, allows to increase the level of thermal comfort, which is not taken into account and evaluated in practice, although the relevant standards for comfort conditions and categories of buildings to ensure comfort have been introduced in Ukraine. This paper analyzes the change in the level of comfort after thermal modernization, determines the category of the building to provide comfortable conditions, as well as identifies the change in the average radiation temperature of the fences, as one of the main factors of PMV change in these conditions.