In this article we deal with the energy renovation of existing school buildings, one of the most relevant and current issue concerning Italian public buildings. The necessity of a re-alignment with the European performance levels, achievable through a renovation of the school buildings stock, of which almost 90% is more than 30 years old, finds the two main obstacles in the lack of a full awareness of the current state of integrity of buildings and in the absence of an effective energy retrofit planning. The aim of this study is to define the most promising renovation strategies applicable to all the school building in Lecco municipality, from both the economy and the energy point of view, through the development of an analysis method, repeatable and applicable to most realities, that allows optimizing and simplifying the energy analysis. The presented research is based on the classification and analysis of the study sample, consisting of 38 school buildings that differ in educational level, age of construction and typological design. The methodology developed allows dividing the sampled schools in homogeneous clusters, each one represented by a reference building, whose energy analysis makes it possible to define the best renovation strategy in terms of cost/benefit. The results obtained provide replicable guidelines useful to the Public Administration in planning of energy retrofit interventions, in defining the total investment amounts and the consequent raising of necessary investments. Specifically the total investment would amount to is an element of 62.971.530, with a calculated economic investment per student equal to is an element of 5.060,0. (C) 2017 Elsevier B.V. All rights reserved.