LowEx-Bestand Analysis

LowEx-Concepts for the Heat Supply of Existing Multi-Family Houses

Funding code: 03SBE0001 A/B/C

Funding period: 06/2016 until 02/2022

Project partner: INATECH – Uni Freiburg, Fraunhofer ISE, KIT



  • Overarching research project as a scientific link connecting all works carried out in the thematic project LowEx-Bestand
  • Ensuring a close exchange of information between the three pillars of the project network: “Analysis”, “Technology” and “Demonstration”


  • Development and demonstration of LowEx systems with heat pumps for the energetic renovation of multi-family houses
  • (Further) development of electric and gas driven heat pumps as well as heat transfer and ventilation systems
  • Rise of profitability and acceleration of the market launch
  • Significant contribution to CO2 objectives in the building sector

Work plan

AP 1: Analysis of the existing multi-family houses and the renovation processes
Systematization of the building types, players and processes

AP 2: Technology and system development
Innovative LowEx components and systems for energetically renovated multi-family houses, typing of system concepts, optimisation by type of building

AP 3: System evaluation
Detailed simulation and derivation of recommendations

AP 4: Demonstration and Monitoring
Innovative LowEx systems for selected multi-family houses, comprehensive data collection and analysis

AP 5: Economic evaluation
Determining the cost-optimized LowEx technology according to the renovation case, analysis of the economic effects

AP 6: IEA-HPP-Annex 50 „Heat Pumps in Multi-Family Buildings“
Development of concepts for usage of heat pumps in renovated and unrenovated multi-family houses


Contact persons

Dr. Stefan Hess
Chair for Solar Energy Systems | Hans-Martin Henning
Department of Sustainable Systems Engineering (INATECH)
Albert-Ludwigs-Universität Freiburg, Faculty of Engineering
+49 (0)761 203 54191

Project Management, Fraunhofer ISE
Dr. Constanze Bongs
Head of the Research Group Building Systems Technology
Department Energy-efficient buildings
Fraunhofer Institute  for Solar Energy Systems ISE
+49 (0)761 4588-5487

Project Management, KIT
Dr. Ferdinand Schmidt
Institute of Applied Thermofluidics (IATF)
Karlsruher Institut für Technologie
+49 (0) 721 608-43026