German Tenants May Cut Rent When Indoor Heat Exceeds 26‑28 °C

During the ongoing heat wave, German tenant organisations say that apartments that become unbearably hot can constitute a rental defect. According to Monika Schmid‑Balzert of the Munich Tenants’ Association, a sustained indoor temperature above 26 °C to 28 °C may qualify as a defect, allowing renters to claim a reduction of up to 20 % of the rent for the affected days. Tenants must document the heat with a “heat protocol” – photos, temperature logs and witness statements – then notify the landlord in writing and suspend full payment until the issue is resolved. The German Tenants’ Association (DMB) stresses that the landlord is obliged to ensure proper summer heat protection according to technical standards, but the right to structural upgrades such as new insulation is not guaranteed.

The guidance applies particularly to top‑floor units with large windows or poorly insulated old‑building apartments, where temperatures rise faster. Each case is judged individually, and tenants risk payment arrears or termination if they reduce rent without proper proof.