Air conditioning in a condominium apartment: do I need the consent of the other owners?

Hot summers are making air conditioning increasingly attractive in Viennese condominium apartments too. With split air conditioners, however, an outdoor unit is regularly mounted on the façade, on the balcony or somewhere else outside the apartment.

This raises a question of condominium law: may an apartment owner simply decide this on their own?

In many cases the answer is: No.

The outdoor unit is the decisive point in law

The façade is one of the common parts of the building. If an outdoor unit is mounted there and the outer wall is drilled through for the pipes, the Austrian Supreme Court holds that this is no longer a merely minor alteration.

Under the Condominium Act, the consent of the other apartment owners is required as soon as an alteration could affect their legitimate interests. It does not have to be established that anyone is actually affected. The mere possibility of such an effect can trigger the need for consent.

With air conditioners this concerns in particular interventions in the façade, a change to the external appearance and possible noise.

A majority is not enough

For such an alteration a majority resolution of the owners’ association is not sufficient. As a rule, the consent of all other apartment owners is required.

If this consent is missing, it can be replaced by the court under certain conditions. The court examines in particular whether legitimate interests of other owners are affected and, where common parts of the property are used, whether the alteration is customary or serves an important interest of the apartment owner.

For an air conditioner, silence does not mean consent

Since the 2022 amendment to the Condominium Act there has been a simplified procedure for certain alterations. If the other owners are duly notified and do not object within two months, their consent is deemed given in certain cases listed by law.

This covers, for example, certain shading devices, charging stations, accessibility measures and now also certain photovoltaic systems.

Air conditioners, however, are not on this list. Anyone who informs the other owners of a planned air conditioner and receives no objection within two months cannot assume their consent for that reason alone.

Are hot summers an “important interest”?

This, too, cannot be answered in general terms.

The Supreme Court looks at the specific circumstances of the apartment in question. What can be decisive is whether the air conditioner is necessary to allow a use that meets today’s housing standards.

The mere reference to Vienna’s summers getting hotter, or to attic apartments in particular heating up strongly, is not automatically enough. The Supreme Court has expressly stated that such general considerations say nothing reliable about the specific apartment.

Conversely, the specific circumstances can well speak in favour of approval. For office premises, for example, the Supreme Court has also taken into account occupational health and safety requirements and actual temperatures of around 30 degrees.

A building permit is also required as a rule

Besides the consent of the other owners, an outdoor unit on the façade as a rule also requires a building permit. It changes the external appearance of the building. Noise and the amount of refrigerant can also play a role, and stricter standards apply in conservation zones.

For the building application, the building authority requires the consent of all co-owners of the property. In practice they sign the submitted plans for this. In a condominium building these are all the other apartment owners. If the court has replaced their consent, that decision is as a rule sufficient.

Do not install first and ask afterwards

An air conditioner should therefore not simply be installed with the legal question postponed until later.

If an alteration requiring consent is carried out without it, even a single apartment owner can as a rule demand its removal and the restoration of the previous condition. Whether the air conditioner would in fact have been approvable is not automatically decisive in such proceedings.

Anyone who wants to install a split air conditioner in a condominium apartment should therefore check before installation where the outdoor unit is to be mounted, which common parts of the building are affected, whether the necessary consents and the building permit are in place. If consent is refused, it can then be examined whether replacement by the court has a prospect of success.