If You Notice This, Don't Turn on Your Car's AC: It Needs Cleaning or Service

As temperatures rise, drivers are warned against immediately turning on their car's air conditioning if they notice an unpleasant smell. This odor is typically a sign that moisture has accumulated within the AC system, creating a breeding ground for bacteria and fungi.

Beyond the discomfort of a bad smell, the contaminated air can trigger cold-like symptoms, throat irritation, and sneezing in susceptible individuals. To prevent this, experts recommend disinfecting the air conditioning system at least once every two years, or ideally annually. While taking the car to a professional service center is the safest option, basic cleaning can be performed by car owners themselves.

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The safest option is always to go to a service center, but basic cleaning can be done by drivers themselves, with the help of products available in auto parts stores.

Commercially available disinfectant sprays offer a simple solution. These are usually placed under the passenger side dashboard and activated while the AC is set to recirculation mode with the engine running for about 15 minutes. It's advisable to have a spare key handy to prevent the car from locking itself while the engine is on. These sprays typically cost around six euros.

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Such a spray is most often placed on the floor of the vehicle, near the passenger seat, under the plastic trim.

A more involved method uses cleaning foam. This process requires removing the cabin filter. A portion of the foam is applied to the AC evaporator, while the rest is injected into the ventilation ducts using a provided tube. After letting the foam sit for about half an hour, the engine is started, the AC and fan are set to high, and all vents are opened to thoroughly air out the system. Foam cleaners generally cost around nine euros.

In addition to disinfection, regular replacement of the cabin air filter is crucial, ideally twice a year or at least once in the spring. A clogged filter restricts airflow, reduces ventilation efficiency, and can contribute to persistent odors. If the smell returns quickly after cleaning, or if the AC performs poorly or the cabin remains damp, it is best to consult a professional mechanic, as these could indicate deeper system issues.

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If the unpleasant smell returns soon after cleaning, if the air conditioning cools poorly, or if the vehicle constantly feels damp, it is best to go to a service center.