Imagine how alarming it might be to open your eyes one morning and find raindrops forming on the ceiling above your bed! This occurred regularly to a homeowner in Reno and always happened on the coldest days. The bathroom fan in the hallway also dripped. What was going on?
When warm moist air hits a cold surface, the moisture condenses out of the air – it becomes liquid water. There were two things going on in this house:
- There was no attic insulation over the wall on the north side so the ceiling got extremely cold
- The moisture level in the home was excessively high
People living in dry climates like ours often use a humidifier to make their environment a little more comfortable. These particular homeowners had a powerful humidifier, constantly dumping moisture into the house, causing the relative humidity to jump far above the recommended 30% – 50%. When this warm moist air met the cold surface of the ceiling and the cold metal of the bathroom fan vent in the attic, raindrops formed.
So what could the homeowners do? Two relatively simple steps:
- Insulating the attic properly (especially above the North wall)
- Reducing the level of humidity in the house
Voila! problem solved!