I had a contractor install NEW windows (on the upper storage area) while they were building the garage. They charged an extra $2,000 for "ventilation". The floors, ceiling, walls etc. are all insulated. There is heat (about 15 C.) However, ice forms on the inside of the windows and as it melts the water doesn't evaporate.
I tend to agree with Carl, the window could be faulty. I would suggest contacting the contractor who installed the windows and ask him/her where the windows came from (hopefully a reputable company) and they should have a warrantee. If the contractor won't respond, and you have the manufacturers name ( All-weather windows, Jen-weld, Etc.) you could contact them directly and explain your concerns.
Sorry to hear of your issues.
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