Understanding Shared Property Facade Laws: Condominium AC Approval in Europe

Installing air conditioning in an apartment you own outright is straightforward. Installing it in an apartment that shares walls, a roof, a facade, and a legal co-ownership structure with dozens of neighbours is considerably more complex. Across continental Europe, the apartment building is typically organised as a condominium — a legal co-ownership framework in which each owner holds their private unit while sharing ownership of common parts including the building facade, roof, structural walls, and external appearance. Condominium approval for AC installation in Europe becomes necessary the moment the proposed system requires any modification to those common parts — and most conventional AC systems do.

What makes AC installation in a European condominium legally complex?

The legal complexity stems from the distinction between private and common parts. In a typical European apartment building governed by co-ownership law, the external walls, the facade surfaces (including anything visible from outside), and the structural elements are common parts owned collectively by all co-owners. Any modification to a common part requires the consent of the co-ownership body — expressed through a vote at an Annual General Meeting (AGM) or extraordinary meeting — regardless of whether the modification benefits only one apartment. A wall-mounted AC unit with its external condenser visible on the facade constitutes a modification of a common part in all major European co-ownership legal systems.

The practical implication: fitting a standard wall-mounted split AC with an external condenser in a European apartment almost always requires prior authorisation from the co-ownership AGM. Installing without it exposes the owner to a civil removal order, costs for reinstatement, and complications at resale when the property's technical dossier is audited. The legal risk is real and is regularly enforced — particularly in France, Italy, and Spain where co-ownership law is well-developed and actively litigated.

What is the AGM approval process for AC installation in a French copropriété?

In a French copropriété, any work affecting the common parts — including the building exterior — requires a resolution adopted by the AGM of co-owners (Assemblée Générale des copropriétaires). For AC installation with an external condenser visible on the facade, the relevant article is typically Article 25 or 26 of the 1965 Act, requiring a double majority: more than half the co-owners in number and more than two-thirds of the total co-ownership shares. Failure to obtain this vote before installation can result in an action en justice brought by the syndic or any co-owner for mandatory removal at the installer's cost.

The practical AGM process involves submitting a request to the syndic (the managing agent) at least 21 days before the next AGM so the item can be included on the agenda. Providing a technical specification, photographs of the proposed installation, an electrician's certificate, and a noise assessment (since noise nuisance is a common co-owner objection) substantially improves the probability of the resolution passing. Many French syndicates now have standard clauses allowing reversible portable AC installations without requiring a full AGM vote — a distinction worth checking in the règlement de copropriété before preparing an AGM submission.

Germany's WEG 2020 reform: the minority veto edge case

Germany's WEG reform of December 2020 significantly simplified the co-ownership approval framework, reducing the threshold for most modifications from a qualified majority to a simple majority. Importantly, the reform also introduced the concept of Privilegierte Maßnahmen (privileged measures): specific types of modernisation including EV charging, accessibility adaptations, and broadband installation that individual owners have a right to carry out even against majority opposition. Residential AC installation is not explicitly included in the current privileged list, but German legal commentary increasingly argues that AC installation in a changing climate meets the reasonableness standard that would block minority objections. This remains an evolving area of WEG case law worth monitoring.

How do Italian and Spanish co-ownership laws handle AC facade modifications?

Italian condominium law under Articles 1117–1139 of the Codice Civile defines common parts broadly, explicitly including the external walls, facades, and the building's structural envelope. Any modification visible from outside — including a condenser unit, pipe routing, or bracket — requires assembly approval by a majority of co-owners representing a majority of millesimal quota. Italian courts have consistently held that external AC installations constitute innovations (innovazioni) to common parts rather than permitted modifications to private property, requiring the higher approval threshold under Article 1120 CC.

Spanish condominium law under the Ley de Propiedad Horizontal sets a 3/5 majority threshold for modifications to common elements. Spanish comunidades de propietarios have become increasingly active in enforcing facade uniformity, particularly in newer residential developments where the building's architectural appearance is protected by the comunidad's statutes. In both Italy and Spain, many comunidades/condominii now include explicit AC installation protocols in their reglamentos/regolamenti, specifying approved condenser positions, approved pipe routing paths, and required colour matching — making advance consultation with the administrator essential before any installation.

How does a mobile split portable AC avoid triggering co-ownership approval requirements?

A mobile split portable AC places both the indoor and outdoor units inside the private apartment. The outdoor section — which contains the compressor and condenser — sits on the floor inside a room, corridor, or ventilated cupboard rather than on the shared building facade. The refrigerant hoses route through the private window opening, which is part of the private unit in virtually all European co-ownership frameworks, not a common part. Nothing is bolted to or visible on the shared facade; no common part is modified or encumbered. The installation therefore falls entirely within the private sphere of the individual apartment owner and requires no co-ownership consent.

This legal advantage is specific to the mobile split design. A standard single-hose portable monoblock also avoids facade modification, but its significantly lower efficiency and infiltration-related losses make it a poor long-term cooling solution. A mobile split unit delivers comparable performance to a wall-mounted split — in many cases identical BTU output and SEER rating — while maintaining the full co-ownership legal exemption of an internally-positioned system. For apartment owners in French copropriétés, Italian condominii, and Spanish comunidades, this is not a minor convenience but a genuine resolution of a significant legal obstacle.

The r/legaladvice Europe threads on apartment AC are full of people who installed split systems without AGM approval and are now facing removal orders. The consistent advice from those who have navigated it successfully: use a portable unit that stays entirely inside your flat. Once nothing touches the common parts, the co-ownership body has no legal basis to object.

What documentation should I prepare if I do seek AGM approval for AC installation?

If the preferred installation requires an external condenser and AGM approval is being sought, the quality of the documentation submitted to co-owners substantially affects the probability of the vote passing. Co-owners object most commonly on three grounds: visual impact on the building facade, noise disturbance from the condenser unit, and concerns about structural integrity from bracket fixings. Each of these objections can be pre-empted with appropriate technical documentation.

1. Architectural visualisation or scaled photograph showing the proposed condenser position on the facade, with dimensions and any colour-match cladding proposed — addresses visual impact objections before the meeting.
2. Acoustic report or manufacturer-certified noise data for the condenser unit at the measured distance from neighbouring apartments, demonstrating compliance with local noise ordinances — the most common objection in French and German co-ownership votes.
3. Structural engineer's confirmation that the proposed bracket fixings are appropriate for the wall construction and that no structural elements are affected — addresses objections from owners below or adjacent to the proposed unit position.
4. Planning or building regulation confirmation that no additional consent is required from the municipal authority, and that the installation complies with local regulations on facade appearance and electrical installation.
5. Insurance addendum confirming that the installation is covered under the owner's individual property insurance for any third-party liability arising from the unit — addresses syndic and fellow co-owner liability concerns.

What happens if AC is installed without required condominium approval?

Installing an external AC condenser without the required AGM approval exposes the owner to three material risks. The first is a civil action by the syndic or any co-owner seeking a judicial order for mandatory removal and reinstatement of the facade at the installer's cost — a procedure available under civil codes in France, Italy, Spain, and Germany. The second is a reduction in resale value and complications at notarial completion, where the property's technical conformity dossier is reviewed and any unauthorised modification must be declared or retrospectively regularised. The third is a potential insurance coverage gap: if an unauthorised installation causes damage to a neighbouring property, the owner's insurer may deny the claim on the basis of the unauthorised structural modification.

Retroactive AGM approval — seeking approval after installation rather than before — is legally available in most systems but carries a higher political risk: co-owners who might have approved a prospective request sometimes vote against a retrospective one on principle. The practical and legal advice from co-ownership lawyers across France, Germany, Italy, and Spain is consistent: seek approval before installation, or choose an installation type that does not require it.

For the majority of European apartment dwellers, a mobile split portable AC is not a compromise choice made under legal constraint — it is a technically capable solution that also happens to be legally unproblematic. The combination of no facade modification, no AGM approval requirement, full reversibility, and performance equivalent to a fixed split system makes it the most practical cooling choice for co-ownership properties across all major European legal frameworks.

The Midea PortaSplit-class mobile split units that satisfy all European co-ownership legal requirements — no external fixings, no facade modification, full interior placement — are the units in highest demand across densely built European cities during heatwaves.