At this time of year, keep the aircon on low at setting 1 and not more than 18c, use recirculation as it uses already dried air.

It's cold and their is moisture in your breath!

My Kia does the same.

Also make sure the pollen filter isn't wet.

There will be drains from the heater to allow any A/C condensation to escape - check they aren't blocked.

If the car is parked outdoors overnight, does the screen mist up inside? If it does, damp may be coming from hidden places. If it doesn't, then the condensation is just from breath, damp clothing, shoes, etc. at this time of year.

This is an odd one. I'm sure I've had a car that did that.

Does it do it on warm up? I think mine did. Warm air holds more moisture than cold air and if the windows are still cold you could get extra condensation.

Just keep the aircon on all the time, start off with the distribution to the screen to get that clear, then switch to screen and feet.

If it's automatic, leave it on auto (aircon on) and use demist (screen) if necessary.

Aircon generally doesn't work below about 4C, so just use more heat on the glass.

And set the temp you want.

My aircon is never off, except on the MX-5 when the top is down and air-conditioning England seems extravagant. I've never worn it out or had any problems with it.

If condensation problems persist, look for dampness/water leaks.

Edited by Manatee on 06/02/2018 at 19:00

I would check and do the following:

• If its of the 'dual-zone climate control' models, set both zones to the same temperature (as a mechnical engineer designing A/C systems, having two 'zones' in a car that has an internal area of about 4-5m3 with no hard division between the 'zones', is a waste of time - all they do is fight against eachother, and can, in extreme cases, cause windows to fog up.
• Check all the ventilation intakes on the outside (e.g. by the windscreen wipers) for blockages (leaves, etc) and inside drain holes as others have said and clear any blockages, which will help moisture in the air (mainly you breathing out) to escape.
• Make sure that the windscreen and windows, especially on the inside, are clean, especially free of greasy (finger) marks and dust, as this will help steam up the window affected.
• As others have said, leave the A/C system on 'auto' and at a reasonable temperature (say 20degC +/- 1degC in winter) and only use the air recirculator function when in heavy traffic - when the car starts, this will likely be defaulted to off in winter to stop the car steaming up, and try and let it heat up with it off for as long as you can to help heat the car and remove mositure from your breath.
• Keeping the air-recirculator on for extended periods (more than 10-15 mins) in winter will inevitably lead to the car steaming up, as you're adding moist air from breathing out and not outside air, which, for the most part in winter, is at a far lower relative humidity level compared to inside the car (as well as in summer) - which can more easily steam up in winter due to the far lower temperature that condensation forms (due point).
• The A/C auto system should, if required, automatically demist the front windscreen, but also make sure that the side vents face the side windows in winter to keep them from misting up (many people forget that they change the direction of the vents to face the passenger in summer), and, if necessary, change the mode from auto to 'front windscreen and upper vents' (it may be auto on front windscreen and feet level vents, with a bit on upper vents) and close the middle two vents to get more warm air out of the two side upper vents. This should help - the two centre vents aren't really needed in winter in my view.

This method seems to work in my (admitedly older [mk1 from 2005/6] Mazda3 with climtae controlled A/C) fine.