Moisture vs. Humidity – Understanding The Difference

I never knew there was a difference between moisture and humidity until I begin to familiarize myself with the two. After doing a lot of research, I decided to share what I’ve learned below.

Moisture represents the presence of a liquid containing trace amounts of water. Humidity, on the other hand, is the concentration of water vapor in a gaseous state, present in the air.

What Is The Difference Between Moisture and Humidity?

The terms moisture and humidity are often misused when trying to describe one and other because the two are very similar. To understand the difference, we first need to examine what each of them is and what causes them.


If you use the term moisture in a technical sense, you are defining the presence of liquid in an environment. Although the word encompasses all liquids, it generally means water and typically in trace amounts.

The trace amount of water could be in wood, food products, or just about anything. It’s not technically wrong to use the term moisture to indicate the presence of water in the air, but the term humidity is more accurate.

Moisture is barely noticeable, but its impact is significant. For example, high moisture content can cause damage to a building and may even cause health problems for the occupants.

For instance, too much moisture can cause mold to grow. Mold can grow on practically any type of surface, including cardboard, carpets, drywall, insulation, wooden furniture, magazines, to name a few.  

Also, continuous exposure to moisture can cause the metal to corrode or rust, wood to rot, which can weaken the structure of a home.

Thankfully, with the use of various moisture management strategies, one can prevent or slow down the accumulation of moisture in unwanted places. There are already different types of materials that can help in preventing unwanted moisture depending on factors such as water vapor diffusion, airborne water movement, capillary suction, and gravity.


Humidity is a technical term to indicate the amount of water vapor that is present in the air. Keep in mind that water in its gaseous state is typically invisible to the naked eye. Meteorologists often monitor humidity levels as it may pave the way for a better prediction of fog, dew, or precipitation.

When measuring humidity, three types are widely employed. There’s the specific, relative, and absolute.

Specific humidity indicates the ratio of the total air within an area and the water vapor mass within the same range. Absolute humidity describes the amount of water present in the air. Often it is expressed in grams per kilogram or cubic meter. Relative humidity indicates the current absolute humidity concerning the maximum humidity for the specific temperature. Often it is expressed in terms of percentage.

In most cases, humidity is monitored because it can significantly impact surface life. For example, an animal that is dependent on sweating as a means of regulating body temperature, high humidity environment can impair the process as it can affect the organism’s natural heating or cooling process. The humidex, or also known as the heat index table, better describes the various effects of humidity on an organism.

How To Prevent Moisture In Your Home

  • Opens windows and use fans to circulate airflow.
  • Use air conditioners or dehumidifiers doing those humid summer months.
  • Fix plumbing leaks.
  • Prevent water from getting into your home through cracks, gaps, and holes.
  • Vent your clothes dryer to the outside of your home.
  • Use exhaust fans in both the kitchen and bathroom.

There are a few different things that you can try doing to help prevent moisture in your home.

Is Moisture The Same As Water?

Moisture refers to the amount of water vapor that is in the air. Since moisture is the presence of a liquid and often made up of small traces of water, it is safe to presume that moisture is the same as water in a sense.

Does High Humidity Mean More Moisture?

Because humidity is made up of water vapor, the higher the humidity, the more moisture that is in the air.  Once the humidity level reaches 100%, clouds are no longer able to hold anymore, which is what causes it to rain.

What is an Uncomfortable Humidity Percentage?

Everyone is different, so humidity levels will begin to affect everyone differently. Generally, when the humidity percentage is in the low-60’s to low 70’s, this is when humidity will become uncomfortable for most people. The reason is that higher humidity will make people feel warm and sticky.

Not only can high humidity be uncomfortable, but low humidity can also bring with it a level of discomfort. Low humidity causes your skin to dry out and become itchy.

The American Academy of Allergy Asthma & Immunology (AAAAI), recommends that the humidity level in your home should be between 40 to 50 percent.

What Causes Humidity?

Humidity is the presence of water vapor in the air. It is the amount of moisture in the atmosphere or a gas. Since humidity is water vapor, it must come from areas with lots of water.

So what causes humidity? Well, there are several factors. The main reason is evaporation. Evaporation is the process of turning liquid into vapor. But in this case, it is specifically the evaporation of liquid water into water vapor. Evaporation happens when the water molecules leave the liquid body and become a vapor.

Why do they leave? Well, sometimes, the molecules are separated from the body of water? It is said that on windy days, more evaporation can occur because wind can cause more molecules to become separated from the body of liquid, and it increases the overall volume of air that is in contact with the body of water.

The biggest cause of evaporation, though is heat. Heat causes the energy of atoms and molecules to rise. Just as metals can melt from a solid into a liquid because of heat, water can evaporate because of heat. The reason why heat does this is that it has energy. The energy causes atoms to move more and become more distant from each other, and soon enough, they begin to break away.

The main source of heat for evaporation is the sun. The sun provides enough heat to cause evaporation, which causes water vapor to get into the air, and that eventually causes humidity. Most evaporation takes place in huge bodies of water, such as oceans, rivers, and lakes. They have the greatest surface area of water, and the sun’s heat shines on them and causes evaporation to occur.

It is said that about 90 percent of all evaporation that occurs is from lakes, rivers, and oceans. Also, warmer bodies of water evaporate quicker. In the USA, the east coast is often more humid than the west coast. The reason for this is because of the warm water that comes in from the Gulf, allowing a greater percentage of evaporation to take place, causing a more humid feel in the air.

As the weather and sun begin to get hotter, evaporation increases, and humidity increases. Although humidity increases because of evaporation, there is a limit to it. When there are too much humidity and too much vapor in the air, soon clouds begin to form, and when enough water gathers in the clouds, rain comes down. Because of this, the humidity decreases, and the cycle begins again.

Humidity occurs in all corners of the planet. But the most humid places are those that have large bodies of water and have a hot climate. Even though deserts have hot climates, their humidity is usually near zero since they rarely have any water vapor in the first place. Deserts are dry, so it cannot be humid. Although tundras are covered by snow, surprisingly they too have very low humidity because it is difficult for snow to evaporate. On the other hand, tropical and swampy landmasses have very high humidity because they usually have bodies of water mixed with high temperatures and some wind.


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