misted up conservatory windows?

I have just had a conservatory built in july.It is now september.
There are 10 window units and double french doors.
In the morning, 4 of the 10 windows and one of the french doors are misted up on the outside of the outer pane.. In order to see out I have to go and wipe them or wait till about 10am til the water evaporates off.
Not all the unit mist and not all on the same side either. It's random, so which ones could be faulty, the ones that mist up or the ones that don't.