Apartment Facade Air Conditioner Regulations in Europe

Every summer, thousands of European apartment dwellers are refused permission to install a wall split by their building management — and incorrectly conclude that air conditioning is impossible for them. Apartment facade air conditioner regulations do prohibit external condenser units on shared facades in most European condominium and leasehold frameworks, but they say almost nothing about portable split installations that leave the building's exterior completely unaltered. Understanding the precise boundary between what is regulated and what is not is the key to cooling your apartment legally.

What Makes an External AC Installation a Facade Modification?

Any permanent fixture attached to, or visibly penetrating, the exterior face of an apartment building is generally classified as a facade modification under European condominium and building regulations. This includes outdoor split-AC condenser units, support brackets, and refrigerant line penetrations through the exterior wall or parapet. Internal window-routed installations that leave no permanent mark on the facade fall outside this definition in most jurisdictions.

The legal distinction hinges on two concepts that appear in most European condominium laws: the common parts (parties communes in France, gemeinschaftliches Eigentum in Germany, common parts in UK leasehold) and alterations to the external appearance. An external condenser unit modifies both: it is physically attached to the building facade (a common part) and changes the visual appearance of the exterior. A portable split outdoor module sitting on your private window sill, connected to the indoor unit via a conduit that passes through your private window opening, touches neither common part.

How Do Apartment Facade Regulations Differ Across European Countries?

The regulatory landscape varies significantly by jurisdiction, but the pattern is consistent: external permanent installations require collective approval, while reversible private-window installations do not. The table below summarises the applicable legal framework, the approval body, and the treatment of mobile split installations in five major European markets, based on published legislation and standard legal commentary in each jurisdiction.

The French copropriété framework deserves particular attention because it is the most precisely articulated. Article 25 of the 1965 law requires a two-thirds majority vote for any transformation, addition, or improvement affecting the common parts or the exterior appearance of the building. A wall-mounted outdoor condenser unit meets both criteria: the facade wall is a common part, and the unit visibly alters the exterior. A portable split module on a private balcony sill or routed through a private window meets neither. French legal commentary (jurisprudence) consistently confirms this distinction.

The 2020 reform of Germany's WEG (Wohnungseigentumsgesetz) introduced a new provision allowing individual owners to demand consent for energy-efficiency measures including heat pump installations. However, this provision facilitates approval for qualifying installations rather than removing the approval requirement — and portable split installations through private windows were already unregulated before 2020. The WEG reform is therefore most relevant for owners seeking to install fixed wall splits on shared facades, not for those using mobile split technology.

Rooftop Terrace Placements: The Bypass Route in Multi-Storey Buildings

If your apartment includes private access to a rooftop terrace or roof garden — common in penthouse-floor units in French, Italian, and Dutch apartment buildings — placing the portable split outdoor module there entirely avoids the facade question. The roof terrace is typically designated as private appurtenance in the property deed, meaning installations on it are treated the same as installations inside your flat. The conduit runs from the indoor unit vertically through a ceiling void or utility chase to the rooftop, which in older buildings with accessible floor-to-ceiling service voids can be achieved without any structural work. Even in buildings with strict facade restrictions, rooftop placement is consistently permissible and is the route used by HVAC professionals when recommending solutions for top-floor apartments with facade constraints.

How Does a Mobile Split Avoid the Facade Problem Entirely?

A mobile split (portable split) system avoids the facade problem because its outdoor module is not affixed to the building structure and does not require any penetration of the exterior wall. The module sits on the window sill, balcony floor, or railing bracket as a free-standing object, connected to the indoor unit by a conduit bundle that passes through the partially opened window. When removed, the window closes to its original state and the building fabric is unchanged.

The conduit bundle (two insulated refrigerant lines, a power cable, and a control cable in an outer sheath, typically 65–75 mm in total diameter) passes through a panel seal in the window opening — a removable panel that fills the gap left when the window is partly open. This panel is not fixed to the window frame with any adhesive or mechanical fastener, making it straightforwardly reversible. Legally, this installation is the equivalent of leaving a window slightly open: it is entirely within the tenant's or owner's rights over their private dwelling space.

What If You Want a Fixed Split Despite Regulations — Is Approval Ever Granted?

Formal approval for external AC condenser units is occasionally granted in European apartment buildings, but the process is slow, the outcome is uncertain, and the threshold varies sharply by building and jurisdiction. In France, a copropriété assembly typically requires the request to be placed on the formal agenda (ordre du jour) of the annual general meeting, which may be months away. Two-thirds of co-owners by share must vote in favour — a threshold that is rarely met in buildings where other owners fear visual impact on their property value.

In Germany, the 2020 WEG reform created a clearer path: an individual owner can demand that the community consent to a heat pump or AC installation for energy-efficiency reasons, and the community can only refuse on grounds of disproportionate disadvantage to other owners. However, 'disproportionate disadvantage' is legally elastic and facade impact is a recognised ground for refusal in German case law. In practice, approvals under this route take 6–18 months to obtain, spanning one or more annual general meetings.

1. Submit a written request to your building manager (syndic, Hausverwaltung, VvE bestuur) describing the proposed installation, its visual impact, and requesting placement on the next general meeting agenda.
2. Obtain a professional installation quote showing the condenser unit dimensions and proposed facade bracket position, which will be required by the assembly to assess visual impact.
3. Prepare a technical summary showing the energy-efficiency benefit (SEER, annual kWh reduction) under the WEG 2020 energy-efficiency grounds in Germany, or as supporting persuasion in other markets.
4. If the vote fails, appeal the decision through the applicable dispute resolution mechanism — in France via the tribunal judiciaire, in Germany via the Amtsgericht — but note that this adds years and legal cost.
5. In parallel, proceed with a portable split installation that requires no approval, to achieve cooling while the formal process runs.

Waited 18 months trying to get the copropriété to approve a fixed split. Meanwhile bought a portable split unit and ran it through the window. By the time the vote finally passed, I didn't even need the fixed unit anymore.

European renters and apartment owners navigating facade restrictions should not wait for a regulatory process to cool their homes. A mobile split installation requires no approval, no drilling, and no assembly meeting — and performs comparably to a fixed wall split on energy efficiency and noise.