I have been living in the same house ever since it was built in the 1980’s. I have never had any moisture problems in my home until recently. I was very suspicious because i just replaced my old natural draft furnace with a high-efficiency furnace. All of a sudden I was having lots of moisture problems. I first noticed condensation on the windows that had never been there before. Then, I experienced water spots on my hall around my skylights, which was because there seemed to be too much condensation in the attic. I called the HVAC supplier that installed my furnace and told them about the moisture problems. The installers came and checked everything and told me it was all working good. So why was I experiencing these problems? They told me that i had several options. I could purchase a continuous exhaust fan to take away air from my home, but I thought that will end up costing me more on my utility bills, because the warm air in my home would be wasted. We can also run a dehumidifier all of winter, but again, this could be cost prohibitive. My best option was to set up a heat recovery ventilator. This could constantly change out the air in my house, while at the same time get rid of the humidity. I wish someone could have explained this problem to me before I had a high-efficiency furnace installed. I thought I was going to save money on my utility bills. Instead I ended up having a bunch more problems, and still had to spend more money.