Our house is 6 months old and we wake up every morning to condensation on the inside of the windows. We have noticed mildew growth where the water collects. I have read the previous questions and responses to the similar problems. We do not want to resort to using a dehumidifier if at all possible, and we are now trying some of the hints given in previous responses. The basement is not finished. We live in southern Ontario. Obviously, our house is airtight. Is this "problem" the responsiblity of the builder to fix? And if so, how?