In this study, a procedure for selecting the optimal heat-accumulating material based on phase transitions for the economical maintenance of poultry farms by applying ANOVA to complex solid bodies’ thermodynamic parameters is described. The relevance of the topic is due to its importance for the development of an energy-saving technology based on the release or absorption of significant heat during the crystallization or melting of materials. The applicability of one-way ANOVA for the selection of the optimal material with a specific functional purpose was demonstrated. As result, the best composition for maintaining a normal temperature regime in poultry farms that could meet all the requirements imposed on heat-storage materials was determined. It was found that magnesium sulphate heptahydrate is such a material.