Has anybody had problems with their air con??

Yesterday morning @ 06:30 it was 21c so naturally I had the air con running with re-circulation on... travelled about 15 mins on the motorway and the wife decided it was too cold so I turned it off for a while.

About 10 mins later I turned it back on, as I was getting the 'boil in a bag' feeling and when I did steam/smoke came out of the front dash vents It stopped after a few seconds and it hasn't done it since but I just wondered if anyone knew what it could be?? Should I be concerned??