The aspect of energy efficiency isone of the most actualfor Russia. Usage of thermal pumps allows to receive energy for functioning of buildings and constructions’ engineering systems. Questions of definition of thermal pumps efficiency indicators and allocation of ways for increasing their functioning are consideredin this article. Operation of the vapor-compression thermal pump is carried out and the main indicators for energy saving are given. Literature about optimization of parameters of functioning thermal pumps isanalysed. And as a result recommendations about an assessment of thermal pumps’efficiency and about definition of terms of their payback aremade.