7 Signs Of High Relative Humidity In Your Home

Moisture is one of the greatest enemies to any home, if not the greatest. Controlling moisture in the home is key to maintaining the health and durability of the home. It is extremely important for homeowners to know what signs indicate high relative humidity in order to address it immediately.


Here are 7 signs that point to excessive moisture in your home.

Condensation on windows

If you notice that your windows look moist or foggy, this is a sign of high relative humidity in the home. When the humidity level in the home is high in comparison to the temperature outside, noticeable amounts of moisture will form on the windows. It’s the same effect of taking a hot shower and the glass fogs up. The warm and moist air inside of the shower comes into contact with a cool surface causing condensation on the glass.

Musty odors

High Relative Humidity can cause mold and mildew growth in your home. The presence of mold can leave a musty smell in your home. Since mold needs moisture to grow, musty smells can absolutely be a sign of moisture issues in your home, particularly in the form of high relative humidity.

Water stains or discoloration on walls or ceilings

When relative humidity rises, excess moisture can roam in your home in the form of water vapor. Water vapor can collect on walls and ceilings causing water stains or discoloration.

Visible Mold growth

Environments with a high relative humidity are perfect for mold to thrive in. Mold travels through the air as tiny little spores. When these spores land on a moist surface, mold begins to reproduce. If you notice mold growing on surfaces in your home, it may be a sign that the humidity levels are too high or a water leak may be present.

Increased Sickness and Allergic Reactions

High levels of Relative Humidity can cause allergens like dust mites and mold spores to thrive, which can trigger allergic reactions. When Relative Humidity is high, breathing becomes increasingly difficult, especially for those with respiratory issues like asthma.

Increased Presence of Critters

When Relative Humidity is high, you will begin to see an increased presence of bugs, termites, rodents, roaches, and other types of infestation in the home. Some of these creepy crawlers can bring bacteria and disease into the home. Others, like termites, can cause significant structural damage to your home costing thousands in repairs.

Warped wood

Moisture in the air can soak into wood and cause it to warp. With elevated relative humidity in the home, you may begin to notice warpage in your wood floors, doors, or even your furniture.


The best solution to lowering the Relative Humidity in your home is to make sure that your HVAC system is running properly as it is a whole house dehumidifier. In addition, you can use a separate dehumidifier to control relative humidity in areas like basements where the HVAC system may not be needed to run as much due to less usage of the space. If you have a basement and would like to learn more, read our post on Running a Dehumidifier in your basement.


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