A qualified rent index has been in force for privately financed apartments in the city since January 1, 2020. This is drawn up in accordance with recognized scientific principles and jointly approved by the City of Aachen and representatives of landlords' and tenants' interests. A qualified rent index must be adjusted to market developments every two years and revised after four years.

The first update of the qualified rent index took place in 2022, followed by a comprehensive revision in 2024. The updated, qualified rent index comes into force on January 1, 2026.

The City of Aachen's rent index working group, consisting of the Department of Housing, Social Affairs and Integration and the voting members Mieterschutzverein für Aachen und Umgegend e.V. and Aachener Haus & Grundbesitzerverein e.V., has therefore commissioned DOMUS Consult Wirtschaftsberatungsgesellschaft mbH to update the qualified rent index.

A representative random sample was carried out when updating the qualified rent index. A total of 1,000 households were surveyed. As a result, it was determined that the average increase in rents is 6.3 percent.

The qualified rent index 2026 and the corresponding online calculator are now available on the city's website at www.aachen.de/mietspiegel.