The air con unit has a drain on it . You can sometimes see water dripping from under the car. This can block and hold water so if air con is not used will smell . You can also have it cleaned I think they spray something into it to kill any germs that can build up. I think the antara air con must suffer with water build up as a lot of people have trouble with misting up of the windscreen. With modern car it is better to use the air con quite oftern as not using it to save fuel will cost more in the long run as not using it cause problems with it.
Are car is a year old and we have never had trouble with the air con or misting so hope you get yours sorted
Are car is a year old and we have never had trouble with the air con or misting so hope you get yours sorted