I have a serious problem concerning a basement. My basement is detached from my house. It had a house on top but was torn down but we decided to keep the basement for storage. I had a metal roof put on and believe I have it adequately insulated. The basement has the waterlines going thru it to the new home we have beside the basement. The area is heated with 2 ventless gas heaters and I have a dehumidifier running 24/7. The problem is the musty stale smell that is not only in the air but is on everything that is being stored. This has caused seasonal decorations such as Christmas ornaments, clothing, and the extra large canning pots etc to be thrown away. I believe that perhaps we need to ventilate the basement but how do we do this without loosing the heat that is necessay to keep water lines from freezing in our northwestern Pennsylvania climate.