Since a few years there is an intensified debate in the Dutch social housing sector about measures to improve the energy efficiency of buildings and individual dwellings. It is generally acknowledged that it is cost-efficient to combine physical measures to improve the energy performance of dwellings with maintenance or improvement activities. Most of these activities take place during void repairs, planned preventive maintenance and renovations. Each can be regarded as an investment opportunity. The allocation of energy improvements between these investment types influences the energy performance of a housing stock in the long term. The central question of this paper is to assess to which extent the energy performance of the Dutch housing stock improves combining these investment types.