Rental value appraisals: why the valuation is becoming ever more difficult

The biggest problem with rental value appraisals today is the availability of comparable data. To determine a market-appropriate rent, we need reliable comparable rents from the respective market segment. Yet many municipalities lack a qualified rent index, and where one exists it often does not cover all dwelling sizes, years of construction or locations. At the same time, the German Federal Court of Justice (BGH) requires the survey to cover the entire municipality and to be based on a representative sample. Appraisals that draw only on individual estates or landlords are unusable in court.

In addition, there is the regulatory complexity. The rent control mechanism (Mietpreisbremse) has been extended until the end of 2029, and each federal state issues its own ordinances with different exceptions. In Hamburg it applies across the board. With every valuation it must be examined whether the control applies and how capping limits or staggered-rent arrangements are to be taken into account. All of this makes rental value appraisals considerably more involved today than just a few years ago. In some cases an expert valuation is simply not possible because the necessary basis of comparable data is missing. Where no reliable data is available, no sound appraisal can be produced either.