The energy refurbishment rate of Stuttgart’s building stock is too lowAbout 80% of Stuttgart’s buildings were constructed before the existence of the first Thermal Insulation Regulation in 1977. As a consequence, a very large energy saving potentialremains unexploited. In addition to the regulations related to energy efficiency in new buildings there are regulations for the energy refurbishment of existing building stock. In the event of an extensive renovation, the primary energy demand of the renovated building should not exceed by more than 15 % the energy demand of a comparable new building. The state of Baden-Württemberg where Stuttgart is situated adopted additional minimum requirements for heating modernisation in existing buildings. When key components of the heating systems are replaced, heat production has to include 15 % of renewable energy.

In 2014, about two thirds of Stuttgart’s residential building stock used gas for heating, followed by oil (15%), district heating (11%) and electricity (10%). Only 2% of residential buildings (generally single-family houses) had a heating system based on renewable energy such as biomass, solar energy or geothermal energy.

The city of Stuttgart has developed a ‘care-free energy renovation package’ for homeowners. The package is applicable for two types of retrofit work – the heating system and/or the building envelope – and it includes the following services:

  • Concept and planning
  • Building and construction
  • Operation and maintenance (for the heating system only)
  • Financing (for the heating system only)
  • Guarantee and assumption of risk.

The package offers a high level of security and flexibility to homeowners in the form of:

  • Standard model contracts and tendering documents developed by the city of Stuttgart.
  • Independent technical and financial advice accompanied by continuous quality control provided by Stuttgart’s Energy Advice Centre (EAC). The EAC guarantees that the contracted craftsmen and building firms comply with the “Stuttgart Retrofit Standard” which was developed to ensure high quality energy renovation.
  • High quality retrofit work isimplemented by the municipal energy utility Stadtwerke Stuttgart(ESCO) and a private company ‘Rahm+’ which is also the general coordinator of the renovation work. The ESCO guarantees the technical building system during the contracting period.
  • An energy supply contractingmodel is offered to homeowners who wish to replace their heating system but cannot or do not want to take out a loan (e.g. due to their age or creditworthiness) or spend their savings. Instead of a loan, they pay a fixed monthly service fee to the ESCO which is the owner of the heating system.
  • Secure energy supply – highly efficient, resource-saving and climate-friendly.
  • Modular contracts – homeowners can benefit from and finance all or part of the proposed services.