Heat demand, in buildings is responsible for a large portion of energy loads in Europe, and building renovations represent an important opportunity to achieve sustainability objectives. Efficient district heat (DH) can represent a cost-effective heat source for buildings. Yet, building heat demand reductions will have implications on sustainable DH production and operation. Analysis is therefore needed to identify cost-effective strategies for low-carbon heat solutions in integrated energy systems. This paper proposes a methodology to investigate different scenarios to 2050 involving integrated heat supply and building envelope investment choices in Torino, Italy and Stockholm, Sweden. The goal is to provide an overview of opportunities for decision makers in elaborating heat strategies including DH. Results show that opportunities exist to achieve consistent energy savings and emissions reduction through strategic combination of DH and building renovation investments. A systems approach is essential to avoid unnecessary investments or early retirement of assets: building renovations should be planned carefully as lower DH base loads could lead to increased running costs, and DH investments need to be adapted to long-term building improvements. Reduced peak loads can allow increased use of low-grade heat, higher merit-order power generation and in some instances cost-effective expansion of DH. (C) 2017 Elsevier Ltd. All rights reserved.