Does your indoor air suddenly seem moist and clammy? If so, you may want to make sure that the humidity levels in your home aren’t too high.

While too little humidity is a problem in its own right, the reverse tends to be more dangerous. High humidity can make your home a breeding ground for mold and mildew. Other warning signs of high humidity are foggy windows, rotting wood, and water stain marks.

Interested in learning what causes high humidity in a house? Here are the top four major causes and how you can deal with them.


While you’re showering, the released moisture mixes with the air to create water vapor. Once the vapor makes contact with a cold surface, it forms droplets of water. The hotter the vapor, the more moisture it will deposit on your cold surfaces.

This is why every hot shower can lead to a potential condensation problem. Other than misting up your windows, this can ruin your wallpaper and invite mold into your home. The simple solution: use less hot water to cut down on the steam coming out.

Poor Ventilation

Poor Ventilation

The quality of your indoor air depends on how good your ventilation is. When everything is working as expected, the air will circulate and refresh itself. With bad ventilation, the air becomes stale and contributes to excess humidity build-up.

Thinking of improving the quality of ventilation in your home? If so, your best bet is to invest in an air purifier. This is a great way to reduce the number of dangerous air pollutants that come into your home from the outside.

Drying Laundry Inside

Did you know that a single load of laundry can contain up to half a gallon of water? By drying your clothes inside, you’re releasing this amount of water into the air in slow motion. Needless to say, all this evaporated water has to go somewhere.

The easiest solution would be to use outdoor drying, which allows the water to dissipate into the air. If this isn’t an option, consider buying a dehumidifier. For example, this dehumidifier will both prevent mold growth and speed up the drying process.

Gas Heaters

Gas Heaters

A gas heater burns gas to produce heat, which is a process called combustion. During combustion, gas heaters create some water vapor and combustion pollutants. Flued gas heaters use a flue or chimney to carry these pollutants into the outside air.

What if you have an unflued gas heater, though? Without a flue, it will release these pollutants directly into your room. This can create a high-humidity environment. Again, the easiest way to deal with this issue is to use a dehumidifier alongside the gas heater.

Other Causes of High Humidity

The above four causes of high humidity are the most common, but there are plenty of others. These include cooking, renovating a home, and living in a coastal area. If you’re not sure what is a high humidity level, anything over 60% is a cause for concern.

Want to learn more about the dangers of high humidity in a home? Interested in other ways of improving your home’s comfort? Keep reading our home-related content!

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