Given the low renewal rate of the building stock, refurbishment of the existing residential buildings is the obvious solution to improve the environmental performance of the building sector. Even though awareness has been raised and building construction industry acknowledges the need for integrated solutions, there is lack of specialised knowledge in the early stages of the strategy development. Moreover, the detailed carrying out of the measures has to fit to the individual project. The paper discusses an integrated approach to refurbishment as a way to upgrade the energy efficiency of the residential stock. The approach aims to integrate the energy performance into the design process of the refurbishment strategy. Different refurbishment options are proposed, systematically organised in a "toolbox" and the impact of each option is assessed. Our methodology gives, in the early design stages, an indication on the retrofitted components' efficiency. Based on multi-residential case-study buildings, we applied the proposed design approach, which resulted in improvement up to 90% on heating energy need. The toolbox supports the decision-making process of refurbishment projects by defining the impact of the choices, resulting in strategies that address all the relevant building components and achieve significant improvement in energy efficiency. (C) 2013 Elsevier B.V. All rights reserved.