In many homes, it is a struggle to keep enough moisture inside the home to maintain an acceptable humidity level for the health and comfort of the occupants. Frequently, humidifiers are installed to add moisture to the air, but their use must be controlled or surface condensation problems will often result when outside temperatures are low. Some indications of surface condensation are:
Frost on door handles and hinges
Water or ice on windows
Damp spots on walls and ceiling
Damp spots on closet walls
Moisture on light fixtures
Moisture on water closets
Moisture on cold water pipes, walls, and floors.
Unfortunately, a dry house may indicate a high leakage rate (depending on the amount of moisture added by the homeowner), which can contribute to concealed condensation. In some newer homes, however, air leakage is controlled so well that removing moisture from the house becomes a problem. This problem is exacerbated by the overuse of humidifiers, resulting in condensation on windows, mold growth, or damp spots on ceilings and room-side surfaces of exterior walls.
Because windows do not provide much resistance to heat loss, they are often the coldest component of a building enclosure and can be an indicator of humidity problems. Because condensation occurs on inside window surfaces whenever the surface temperature falls below the dew point temperature of the room air, window condensation may signal a need to reduce the humidity level in your home.