Research of economic sustainability of different energy refurbishment strategies for an apartment block building

May energy saving derived from the retrofit of a building be able to pay its costs? The paper wants to answer to this simple question, reporting a research started with a simple case study (an Italian social housing quarter, served by a district heating system, which needs - as many others in many other countries - a reasonable refurbishment). The economic sustainability of different retrofitting strategies has been studied: a method to evaluate the costs of refurbishment interventions has been developed through a detailed design of interventions, identifying construction costs thanks to the contribution of a group of selected contractors which gave us reasonable prices representative of a real services offers and assessing the cost-optimal energy levels leading the building towards the energy labels B and A. Both envelope and systems refurbishment works have been investigated. The adopted method allows to chose among different refurbishment options, evaluating them as elementary cases and whole interventions, considering their efficiency by means of the Cost of Conserved Energy (CCE) method and the pay-back of the investments (ROI) by the cash-flow method, analysing different funding systems and incentives. (C) 2014 The Authors. Published by Elsevier Ltd.