Why Is My Room Humid?

Location of the Room

• The location of a room can determine its humidity levels. For example, rooms with exterior walls tend to be more damp and humid, particularly when it rains. This may be due in part to poor foundation sealing as well as a lack of adequate insulation. Interior rooms that are not vented properly may also be humid, but it is more likely that exterior rooms will have higher humidity levels.

Exterior Cracks

• When the exterior finish of a house is cracked or is improperly made, this allows moisture to build up. This moisture has to go somewhere, and it typically seeps inside. This is particularly true of rooms in a basement in which the walls may not have been sealed properly or when a water barrier has not been placed between the foundation and the dirt outside. The moisture buildup raises humidity levels in the room.

Local Climate

• Your local climate also plays a role in how humid the rooms in your house are, especially if you are not using a central cooling system that removes humidity from the air. For example, homes in Louisiana or Florida are much more likely to experience room humidity than homes in Arizona or New Mexico. In this case, it is best to install a dehumidifier to help offset high humidity levels in rooms.

Improperly Vented Appliances

• Home appliances such as washers, dryers and hot-water heaters need to be properly vented. If they are not, or if the vents are clogged, moist air comes back into the house and will typically affect that room and surrounding rooms. Dryers are the most common culprit for this. If you suddenly notice that your room is more humid than normal, check the back of the dryer and the wall to see if the vent has come loose.