BNK/BNG – Assessment system for sustainable small-scale housing/assessment system for sustainable buildings

The BNK/BNG certificate is a seal of quality for sustainable construction that distinguishes residential buildings in Germany. Since 01.01.2023, all residential building sizes can be certified: The Assessment System for Sustainable Small Residential Buildings (BNK) for buildings with 1 to 5 residential units and the Assessment System for Sustainable Buildings (BNG) for buildings with more than 5 residential units.

The certification process runs parallel to the planning and construction of the building. A BNK/BNG auditor accompanies the project from the planning phase through to completion. Certification takes place in several stages:

1. Selection of a BNK/BNG auditor: These are BiRN-trained experts in sustainable building, such as architects, engineers or energy consultants. They provide support in the planning and implementation of sustainability goals.
2. Registration of the project with BiRN: The client registers the building for certification and concludes contracts with the auditor and the BiRN certification body.

Definition of sustainable planning objectives and documentation: Sustainable goals are defined together with the auditor and the necessary documentation is prepared. Once the construction is complete, BiRN checks the documentation and issues the certificate if the audit is successful.

The BNG/BNK certificate is one of the awards that are a prerequisite for obtaining the QNG and therefore also for the Climate-friendly new build promotion with QNG. The KFW offers low-interest loans for climate-friendly new-build projects as part of the Federal Subsidy for Efficient Buildings (BEG). Projects that meet the requirements for QNG-Plus or -Premium and are awarded a sustainability certificate qualify for a higher subsidy.

We answer questions, advise and support you in the successful fulfillment of your BNK/BNG certification. Find out more about the assessment system in relation to the requirement criteria, the certification costs and the certification process.