There is a house that was built in our neighborhood about two years ago. It sat vacant until six months ago. Every morning, when my wife and I go for our walk, I notice that the windows on the home have condensation on them. Doesn't matter what the outdoor temperature is, it happens when it's 70 out or 45 out. They very rarely run the a/c, the windows are almost always open. This happens on the windows that are open as well as the big front picture window. The house is about 3,000 sf + for what it's worth. Any ideas?