Your villa is closed eight months a year. The salt never takes a break.
It is the situation we see most often along the coast: a high-end villa in Théoule, on the Croisette or at Cap d’Antibes, occupied for a few weeks in summer and again at Christmas. Between stays, nobody looks at the outdoor units.
Meanwhile, salt-laden air deposits chlorides on the heat exchangers, day after day. And the failure almost always announces itself at the same moment: the first week of July, when the house fills up and the system has to hold against 35 °C outside.
That is not bad luck. It is a design and follow-up problem, and it is solved before the equipment goes in.
What sea air actually destroys
Airborne chlorides settle on metal surfaces and combine with humidity to form an electrolyte that sharply accelerates corrosion. Four consequences we find on site:
The heat exchanger, first. Aluminium fins bonded to copper tubes form a galvanic couple. In a saline atmosphere the aluminium sacrifices itself: fins whiten, pit, and crumble into powder. Heat exchange collapses long before the unit actually fails — the machine still runs, it just stops cooling.
The fasteners, next. Standard zinc-plated screws rust within a few seasons. A casing that can no longer be removed is a unit that can no longer be serviced properly.
The electronics. The control enclosure is never fully sealed from ambient air. Copper tracks and solder joints oxidise, and the first symptom is almost always an intermittent fault code — one that appears, disappears, and gets ignored until the unit stops for good.
Brackets and mountings. Wall consoles, feet and threaded rods degrade at the same pace. On a rooftop terrace or an overhanging installation, that becomes a safety matter.
Exposure matters more than distance
The international standard ISO 9223 grades atmospheric corrosivity from C1 to CX. High-salinity coastal zones fall under C5, and the most exposed situations under CX. But distance from the shoreline is a crude measure. What really sets the pace of degradation:
- Orientation to the prevailing sea wind. Two units thirty metres apart — one exposed, one shielded by the building — will not age remotely alike.
- Rain washing. Counter-intuitive but decisive: a unit sheltered from rain yet exposed to sea wind accumulates salt and is never rinsed. That is the worst case, and it is common under roof overhangs and in the semi-open plant areas of Riviera villas.
- Height and topography. A terrace overlooking open sea takes far more spray than a lower garden screened by planting.
How we build for the coast
Siting before hardware. This is the most powerful lever and it costs nothing. We look for a position shielded from the prevailing sea wind — behind a low wall, on a sheltered elevation, on the side away from the water — without ever compromising airflow. No coating rescues a badly sited unit.
A factory-treated coil. The four brands we install — Daikin, Toshiba, Mitsubishi and Hitachi — offer versions or options with an anti-corrosion coating applied at the factory across the whole coil block. That is in a different league from an aftermarket spray-on lacquer, which lasts months. We specify it at quotation stage whenever the site warrants it.
A4 stainless steel fixings. A4 (316) stainless — “marine grade” — withstands chlorides where A2 pits. We replace mounting hardware and brackets, and we isolate contact between dissimilar metals so the fixings themselves do not become the next galvanic couple.
Raised, never boxed in. The instinct to build a closed enclosure “to protect it” traps salt, prevents any rain washing, strangles airflow and destroys efficiency. A ventilated shelter, yes; a sealed box, never.
From the field, at Cap d’Antibes
We were called to a villa whose air conditioning “no longer held temperature” after four seasons. From the outside the outdoor unit looked fine. With the casing off, the diagnosis was immediate: only one face of the coil was affected — the one facing open sea. Those fins crumbled under a fingertip; the opposite face was untouched. The signature of a salt-laden prevailing wind.
Our technician also found two bracket screws beginning to shear beneath the head — invisible without dismantling, and the unit was mounted above a terrace.
Rather than drop a new machine into the same spot, we relocated the unit three metres behind an existing wall, replaced the entire mounting in A4 stainless, and put a twice-yearly freshwater rinse in place. The fixing work was not charged: we do not bill for what we should have caught on the first visit.
A servicing routine built for non-resident owners
By the sea, rinsing matters as much as hardware. Deposited salt does not evaporate — it has to be washed off. For villas occupied intermittently, we run maintenance while you are away:
- Freshwater rinsing of the outdoor coil, at low pressure, along the direction of the fins. Never a pressure washer, which flattens the fins and makes the problem permanently worse.
- Two visits a year on exposed coastline, against one inland.
- A pre-arrival commissioning visit, so that a fault surfaces in June rather than in July.
- Inspection of fixings, brackets and the electrical enclosure at every visit, with a photo report sent to you remotely.
We work regularly with Riviera property managers and concierge services, and we fit around their calendar.
Warranty: the part nobody mentions
Manufacturer warranty terms very generally exclude corrosion damage and damage attributable to the installation environment. A standard-specification machine placed on the front line, without documented servicing, stands little chance of being covered when its coil goes.
That is why we document our coastal projects: appropriate equipment specification, justified siting, dated and traceable servicing. A warranty that holds starts with a design that holds.
Where we work
Prestige Air covers the whole Alpes-Maritimes coastline: Cannes and the Croisette, Mandelieu-la-Napoule, Théoule-sur-Mer, Antibes and Cap d’Antibes, Juan-les-Pins, Golfe-Juan, Vallauris, Mougins, Le Cannet and Grasse — from Fréjus to Cagnes-sur-Mer.
Certified QualiPAC (RGE) and F-Gas, our team installs and maintains Daikin, Toshiba, Mitsubishi and Hitachi equipment, in both split and VRV/VRF configurations.
Have your exposure assessed
Whitened coil, loss of capacity, intermittent fault codes? We carry out an exposure survey and tell you plainly whether the installation can be saved or whether it needs replacing with equipment suited to the site.