Rising summer temperatures are leading to a growing demand for cooling systems in residential properties. According to the Federal Statistical Office, only 4.3 per cent of dwellings completed in 2025 were equipped with a cooling system. Ten years prior, this figure was merely 1.9 per cent. This development highlights the increasing relevance of retrofitting air conditioning in existing dwellings.
Permanently installed split air conditioning systems, consisting of an indoor and an outdoor unit, require particular attention. Not only legal but also technical aspects are important here, as installation often involves structural interventions, such as wall breakthroughs for pipes and condensate drainage. This can affect landlords, neighbours, and the homeowners' association (WEG).
Solicitor Annett Engel-Lindner of the IVD points out that before installing air conditioning in rental flats and homeowners' associations, permits, resolutions, or technical proofs must be clarified. Otherwise, attempts at air conditioning can lead to legal disputes.
Legal Aspects in Homeowners' Associations and Tenancy Agreements
In homeowners' associations, it is crucial whether common property is affected. This includes structural components such as facades, external walls, roofs, balcony railings, or communal pipe routes. Structural alterations to common property generally require a resolution from the homeowners' association. Owners should therefore only commission installation after transparent agreement with the association.
Tenants are obliged to obtain the landlord's consent before installing a permanently fitted air conditioning system. This applies particularly to structural interventions, alterations to external components, or the visible attachment of an outdoor unit. Typical points of conflict include noise emissions, visual alterations, necessary drilling, pipe routing, condensate drainage, electricity consumption, maintenance, and potential future removal. Detailed technical documentation regarding the installation location, noise development, professional installation, and condensate drainage must be provided for approval.
Alternative and Preventive Measures
Mobile air conditioning units represent an alternative, but are also not without challenges. They can cause noise, require an exhaust air duct, and often have high energy consumption. Detailed planning and documentation, as well as the early involvement of all parties concerned, minimise legal risks and potential conflicts.
- —Checking whether common property (façade, external wall, balcony) is affected by split air conditioning systems.
- —In the WEG, the resolution status, the declaration of division, and possible association regulations must be clarified beforehand.
- —Obtaining landlord's consent before installation in rental flats.
- —Documentation of technical specifications, sound insulation data, installation location, and condensate drainage.
