Air Conditioning and Home Insurance: Who Pays When Your AC Causes Water Damage?

There's plenty of talk about the purchase price of an air conditioner, the 5.5% VAT rate, subsidies and servicing. Far less about what happens the day the installation causes damage. And yet it has become a common source of disputes: ever since France's residential stock of reversible split systems exploded, insurers have recorded a marked rise in claims mentioning an air conditioner or an air-to-air heat pump.

The typical scenario is anything but spectacular. It's almost never a fire or an explosion. It's a condensate drain pipe clogged with algae, a tray that overflows, and twenty litres of water working their way through a ceiling over three days of a heatwave. Average cost recorded by loss adjusters for this type of claim in a flat: between €1,500 and €6,000 once the plasterboard, the paint and sometimes the neighbour's wooden flooring have been redone.

The question that follows is always the same: who pays? And the answer depends on three things — the technical cause of the failure, the age of the installation, and above all whether or not you declared the equipment to your insurer.

Claim number one: condensate

You need to understand the mechanism to understand the dispute.

An indoor air conditioning unit running in cooling mode dehumidifies the air. Moisture condenses on the heat exchanger, drips into a tray, and drains away through a flexible pipe — either outside by gravity, or into a wastewater drain via a condensate pump. A 3.5 kW wall-mounted split in a humid home easily produces 1 to 2 litres of water per hour during a heatwave. Over a day, that's a bucketful.

Three classic failures:

1. The pipe clogs up. Condensate is lukewarm standing water: biofilms and algae develop in it within a few weeks. The tray overflows and water runs down the inside wall.
2. The fall is insufficient. A poorly installed gravity drain (slope below 1%, or a back-fall along part of the run) creates a pocket of retained water. Same effect.
3. The condensate pump fails. It's an electrical device with a finite lifespan, and many have no high-level cut-out to shut down the compressor.

In a block of flats, water never stays in your home: it passes through the slab or travels along service ducts. The claim immediately becomes a two-party — or even three-party — file.

What insurance covers, in principle

The water damage cover in any multi-risk home insurance policy covers damage caused by "leaks, ruptures, overflows or blockages of pipes, water-using appliances and installations". An air conditioner producing condensate falls into this category with almost every French insurer: it is a water-using appliance.

In practice, in a flat:

Who is affected	Who pays out
Your own decorative finishes (paint, flooring)	Your home policy, water damage cover
Damage in the flat below	Your public liability cover, via the IRSI convention
The air conditioning unit itself	Rarely: it is the item that caused the claim

That last point always comes as a surprise. Home insurance repairs the consequences of water damage, not the cause. If the condensate pump has burned out, replacing it is at your expense (unless you have "machinery breakdown" cover or a specific extension).

The IRSI convention: know it before you call

Since 2018, water damage between neighbours or within a co-ownership has been handled under the IRSI convention (Indemnisation et Recours des Sinistres Immeuble), which replaced CIDRE. The principle: for claims up to €5,000 excl. VAT in damage, the insurer of the occupier of the damaged premises handles and pays out directly, with no recourse against the party responsible. Above that threshold, recourse becomes possible again.

That means two things for you:

• Under €5,000, the neighbour below is compensated by their own insurer, which defuses a great many conflicts. You are not being "sued".
• But the claim is still recorded in your name in your policy's claims history. Three water damage claims in five years, and non-renewal at the anniversary date becomes a real possibility.

The blind spot: did you declare your installation?

This is where many cases get complicated.

A home insurance policy is based on declarations: floor area, number of rooms, type of dwelling, presence of a conservatory, a swimming pool, a fireplace. Air conditioning hardly ever appears on standard questionnaires — so in the vast majority of cases, nothing obliges you to declare it spontaneously.

Watch out, however, for two situations:

• The questionnaire does ask the question. Some insurers, since 2025, have added a "heat pump / fixed air conditioning" line. If the question is asked and you answer no while you do have such equipment, article L.113-8 of the French Insurance Code allows the policy to be declared void for intentional misrepresentation. It's rare, but it's ruinous.
• The value of the equipment changes your contents or buildings sum insured. An €8,000 multi-split air-to-air heat pump installed in a house is not a trivial matter if you want it covered in the event of fire or storm.

The sensible move: send a simple email to your insurer mentioning the installation, its date, its output and the installer's name, and keep the acknowledgement of receipt. It costs nothing and shuts down any later argument.

The exclusion that sinks claims: lack of maintenance

Here's the clause to read before all the others. Every home insurance policy excludes, in one wording or another, damage resulting from a demonstrable failure to maintain or repair on the part of the policyholder.

With air conditioning, the loss adjuster will look for exactly three things:

1. The maintenance log. Under the 2020 decree codified in articles R.224-59-1 et seq. of the French Environmental Code, servicing is mandatory every two years for air conditioning systems and heat pumps with a rated output between 4 and 70 kW. The professional issues a certificate. Without that certificate, your position is very uncomfortable.
2. The condition of the condensate circuit. A pipe colonised by thick biofilm is the signature of years without cleaning.
3. Compliance of the installation. Fall, mountings, trap, presence of an overflow cut-out.

In practice, a well-documented file defends itself. Keep in a single folder — physical or scanned — the installation invoice, the refrigeration engineer's certificate of competence, the servicing certificates and photos of the installation. Many homeowners keep all of this in a dedicated folder for administrative documents, which seems trivial until the day the adjuster asks for five documents within forty-eight hours.

Between professional visits, the routine upkeep you can handle yourself hugely reduces the risk: rinsing the filters, dusting the outdoor unit, and above all treating the condensate circuit. Anti-algae tablets for condensate trays, dropped into the tray at the start of the season, markedly reduce biofilm formation — it's the single most cost-effective step on the whole list.

Outdoor unit: storm, hail, theft, falling

The outdoor unit is exposed, heavy (35 to 60 kg for a standard single-split), and mounted either on the ground on feet or on a wall bracket. It concentrates several distinct risks.