In the past decade the average Dutch housing costs for tenants increased. This increase is almost completely attributable to the higher energy costs. The Dutch government, Aedes and the Woonbond wishes to keep the housing costs manageable. And, intend to manage the housing costs by promoting energy savings in the existing housing stock. These energy savings relate to building-related energy consumption, in particular, space heating, hot tap water and ventilation.The housing associations sector therefore faces a major investment challenge, with the objective of keeping housing costs manageable for Dutch tenants. This research aims to contribute to investments in the energy quality of existing housing stock, by: Designing an instrument that provides insight into, and support in making, investment decisions. These decisions include investments to improve the energy quality of existing housing stock of housing associations. The aim is to keep housing costs manageable for Dutch tenants.