aircon problem

[Hocky]

We are experiencing cold winter weather here now and I find it takes too long for the misted up windscreen to be cleared after the aircon is switched on. This is on the inside surface. The rotary switch was turned to the top , windscreen direction of airflow, the fan speed was at almost full blast, the top dehumidifier button on the dash was switched on and the red light was lighted. I had to wait about 5 minutes and nothing happenned, so I drove off before the windscreen cleared up completely(quite dangerous). The temperature was only about 10 degrees Celcius and not raining. Is something wrong with it? We don't have the very cold weather like in Germany or Canada, so why doesn't it work faster like in our Corolla and Camry which only take 2 minutes to completely clear? Also the rear screen demister takes quite long to clear too. Is this due to the tinting done recently? It was faster before the tinting was done.

!994 Euro C180 Elegance auto(193,000kms).