I had my car serviced and I accidentally agreed to have some sort of service called "A/C Vent Mist Service" done. They described the service as cleaning your car's A/C vents and removing things that irritate your allergies and so on.

But after getting the bill I kind of regret having the service because it seems expensive and not worth the $80 cost (25 minutes totaling $55 and $25 parts).

What is "A/C Vent Mist Service"?

Is this service only needed for cars that have really bad smell maybe? my car is new so maybe I should have avoided it...

  • 1
    I’m pretty sure they spray some sort of disinfectant into the HVAC (Heating, Ventilation, Air Conditioning) Air inlet. Turn on panel mode (recirc off). Turn on high blower. Spray the whole can in at windshield wiper area until empty. cost $12 = $68 profit. Have a nice day.
    – zipzit
    Jan 31, 2018 at 5:26
  • They likely change the interior filter if it has one . The first car I had with one , I did not realize it was there until i had driven about 40,000 miles. Mar 22, 2020 at 20:35

4 Answers 4


The way the service should work is as follows.

If your car is equipped with a cabin air filter, that filter is removed. A special machine is put on the passenger floor. The AC system is set to recirculate which usually pulls air from the passenger floor. When the machine is switched on it generates a mist of a disinfectant with some pleasant smell to it. Then they run this for some time. After they are done a new set of cabin air filters is installed.

The service is controversial because it is difficult to definitively say that it does something. The service is typically performed if you have very severe allergies or there is a bad smell in the dash.

PS if you have a bad smell, an ozone service is much better. The service is hard to find and tends to be expensive but it works really well.

  • I 2nd the effectiveness of the ozone treatment. I once had a really bad smelling A/C, which i'd describe best as a concentrated perfume of wet dogs. An ozone treatment almost completely got rid of the smell.
    – Bart
    Jan 31, 2018 at 11:26

Take a look at the question here. It's common for A/C's to smell like wet dogs, fungus, or any other unpleasant equivalent smell. It develops over time, and worse if the A/C is used only once in a while. Services like you describe are meant to remove that smell. I once had a car that really smelt bad, and getting an ozone treatment almost completely removed the smell.

When the A/C is on, air drawn by your blower is led through the A/C's evaporator to cool it down. Because the evaporator cools down the air, moisture is removed from the air. That moisture falls on the evaporator, creating a breeding ground for fungi and bacteria. They cause the unpleasant smell, and may trigger alergic reactions or even sickness on some people. If you didn't experience those things, the treatment they gave you may have been completely unnecessary.

It's possible that they inlclude the treatment in their general service jobs, but i'd find it bad practice if they don't confirm the need for such a treament with you beforehand. Specially when the costs for it are as high as $80.


Ozone treatments can be effective in destroying "life" in a car. Bacteria, fungi, bugs, etc. However, aside from the human health risk, which is really only a factor during the treatment and immediately after (while the gas dissipates), there are vehicle risks.

The primary vehicle risk is oxidation of materials in the car. For example, the "rubbery" material on VW dashboards gets tackier. Seals can deteriorate. Trim may be affected. Fabrics do not seem to be impacted as much, but pockets with elastic may loose some of their elasticity.

For DIYers, I understand from third parties, that there are emerging restrictions on sale and use of such equipment, and in a home or apartment setting there have been a couple of deaths.


https://youtu.be/EDVY2_kZyck Watch the video. You didn't get screwed. The cost of the bottle is $15. The machine to administer is $250 and they have to pay a tech to apply. The fragrance is an after thought. It's a disinfectant.

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