Cold Air Blowing

Berfore I do my complaining I have to say, I love the company I work for. The ownership is amazing, they do a lot for us, and I have never had a job I feel as appreciated as I do here.
With that being said. I do not understand why there is cold air gushing out of the vent above my desk in the middle of winter. I freeze to death every day at work. Even in the summer I wear long sleeves because it is so cold. But during the summer I can understand the air conditioning being on. But in the middle of winter? I just don't get it. They have people in here trying to fix it from time to time, but it's always freezing cold. I have a space heater under my desk, but it just doesn't always do it for me. I realize some of you may be thinking, well you are always cold. True, but I am not the only one freezing here. Some people have put up cardboard to direct the vents away from their desk. It just doesn't make sense to me why they can't just turn off the AC in the winter like I do at home. It wastes loads of money to turn on the heat and then turn on the AC, over and over again. I don't get why this can't be fixed. But for some reason I am doomed to freeze at work forever.