Consulting expert for energy-efficient buildings and quality management.

As independent consulting engineers we focus on energy-saving buildings, ecological constructions and quality management. We mainly offer speaker services and expertise, which also include standardisation processes. Furthermore, we also offer consultations and special calculations, for colleagues as well of course.


Our office is acutally not regularly staffed. After more than 25 years at Energiebuendel and a whole year in continuous operation we are taking some time out to work on existing orders in peace. We will only accept new orders again after summer from October 2024. Smaller consultaions are of course still possible for existing customers.

Expert reports

We write expert reports on the calculation of energy balances (all German and general European calculation procedures), the thermal behaviour of buildings or rooms and the energy consumption of buildings. We also resolve the issue surrounding the reason(s) for moisture damage in your insulated building parts.

Energy consumption vs. energy requirement

For the investigation of deviations from planning values and real consumption values.

Standardisation and research

We support you in standardisation committees and research projects with questions about energy-efficient buildings.

Advanced training and skill enhancement

As a speaker Mr Stelzer focuses on teaching new knowledge, new technical and public rules and regulations for colleagues that work on the topic of energy efficiency.


Climate change is progressing dramatically and there are many insights into this phenomenon. Mr Stelzer provides presentations on motivation for energy-efficient buildings or best practice examples.


Mr. Stelzer offers these in a variety of topics about energy-efficient and ecological construction.

  • Quality management
  • Systems engineering
  • Passive house designer (CEPH)
  • Building physics and thermal bridges
  • Energy balance and lifecycle assessment

Software workshops

Nowadays the design of good buildings is only possible with special software. For some software products Mr. Stelzer offers user workshops including the theoretical base.

  • Thermal bridge calculation with several software products
  • Passive house planning package (PHPP)
  • ... and others

Special calculations as a service

We support you with special calculations and simulations for your projects as an energy consultant. Especially if these calculations are rarely performed special services for you.

Energy consultant and quality management

We offer all services, including public funding in Germany in the field of ecological constructions for healthy living. We support you in achieving new passive houses and nearly zero energy buildings or in refurbishments with passive house components. We are listed on the "Energie-Effizienz-Experten" list of dena.

Dipl.-Ing. Friedemann Stelzer

Founded in Cologne in 1998, the consultants have been based in Reutlingen since 2007 and offer their services throughout Europe.


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+49 (0)7121 382082-6
fax +49 (0)7121 382082-7