Mist comming from Air conditioning

[guest806]

Hi, whilst driving the car today, i had the fan on with the air flow pointing to the floor and face.  I put the air conditioning on and noticed a mist coming from the top center vents.  This disappeared quite quickly but i switched the air conditioning off.  Several tries to reproduced it indicates it only happens when the fan is on and the air flow is top and bottom.

Any ideas?  Is this still safe to use?

Previous usage is quite regular once or twice a week.

Thanks

[caseyjones]

Almost certainly just condensation. Over a period of time the a/c will dry the air in the car; that's why it's good to use it for demisting windows, even when the weather's cold and you have the heating on as well. However, when you first turn it on, the initial blast of cold air will quickly cool the warm, humid air immediately adjacent to the outlets and condensation may form. This will quickly disperse, as you noticed. As long as the a/c is functioning correctly and there are no funny smells or noises I wouldn't worry about it.

[chrisc]

This last answer is spot on.  If, when it is warm outside, you switch on the aircon for few mins, turn it off, wait 2-3 mins and switch it back on, condensate will appear out the vents for a few seconds.  Hot air contains more moisture than cold, so that is what you see.

Here in SA, it is often above 35⁰ in summer and you can create clouds of condensation from the vents by doing what I described above.  I have teased nervous passengers by telling them to get out the fire extinguisher when this white cloud appears!

[guest806]

Thanks all.