CC problem?

When It's winter I usually set the CC to auto +25 C. Never had problems, but today I noticed it still being quite cold inside after a 20 minute ride. It wasn't that bad, but it felt a bit colder then usually. On my way back I noticed the rear passenger windows misting up A bit too. I checked my vent's. All were open and bļowing in the usual direction. 

It was quite cold outside today, about -6C, but some days in January were even colder and I didn't experience anything like this. I have done almost 29K kilometers with my Fabia, usually with A/C on. Has anyone experienced anything similar and what could be the problem? I have service coming up at 30K, so I'll probably be pointing that out.