Condensation occurs when there is a difference between the inside and outside temperatures of a confined space and there is a waterproof barrier between them. For example, on cold nights when you have the heater on in your house the inside of your windows develop condensation. This scenario also extends to the use of swags and tents. No swag design can eliminate condensation but you can minimize the chance of condensation by slightly opening the window of the swag to enable airflow on cold nights.