This manuscript is part of the research project "Integrated Design for Energy Efficient Housing Reconstruction." It exposes the diagnosis of energy and construction conditions of dwellings of 3 regions in the south central area of Chile, which was the most affected by the earthquake of February 27th, 2010. With this aim, it reviews predominant characteristics of the building envelopes in 22 cities. It analyzes energy performance and it recommends thermal improvements for dwellings either under construction stage or during occupancy stage, which are critical for energy savings and efficiency. It proposes strategies to improve energy efficiency through vertical envelopes, with a base case and two comparative scenarios. It proposes economic, constructive and architectural planning strategies, with the possibilities of social and financial implementation, which could help substantially to achieve energy efficiency.