Why is Humidity Higher Inside Than Outside?

There’s no hiding humidity in the air. One step outside and your skin is instantly sticky, and your hair is a disaster. Usually, going inside provides some refuge from the dampness in the air, but sometimes, the humidity inside can be just as high as the humidity outside, if not more.

In most cases, humidity is often higher inside than outside when the air conditioner is battling poor ventilation. Humidity can increase indoors if the walls aren’t properly sealed, allowing extra moisture to get in. Also, running certain appliances in your home may lead to an increased level of humidity.  

Uncomfortable levels of humidity in your home can be very annoying. Humidity can cause all kinds of issues within your home, not just to your hair and skin.

It can damage walls, warped floors, and aggravate allergies. If you’re interested in why the humidity is higher inside your home, than it is outside, keep reading. 

Why is it More Humid Inside than Outside?

Nothing is worse than attempting to escape the humidity by stepping indoors, only to find that it’s more humid inside. Up next, we’ll go over a few possibilities that might explain why it’s more humid indoors than outdoors

Structural Issues

Issues in the structure of your home are likely to add to the increased humidity. Places like your windows and doors may be allowing unwanted moisture inside. Over time, this unwanted moisture then saturates your air with water vapor. 

Air that has a high water saturation will always make the room feel humid and uncomfortable. Luckily, Increased humidity due to structural issues can be avoided fairly easily.

How to Remedy This Situation

Weatherstripping your windows and doors is a pretty easy task and will certainly lower the humidity levels of your home. 

If you install weatherstrips around the windows and doors of your home, then you will notice a decrease in the level of humidity present. The reason behind this is the fact that there is an airtight seal that keeps excess humidity out of your home. 

Running Certain Appliances

Some of the appliances in your home are likely to cause humidity to rise inside. These are appliances like sinks, showers, and washing machines. The reason behind this is the fact that each of these appliances uses water. 

Just like with structural issues, that excess water that is leftover will saturate the air in the home, which will leave you with high humidity levels.

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Preventing humidity from rising on account of your appliances is also easy, and quite frankly, very similar to the prevention method mentioned above. 

How to Remedy This Situation

Caulking is very similar to weatherstripping. The only difference is that it’s used on different surfaces. The surfaces that these are used on are high moisture areas inside your home. Areas such as your faucet, toilet, tubs, and more. 

These are areas in which there is typically a constant flow of water coming through. This can ultimately lead to water becoming saturated in the air, making the air more humid. 

If you use this method, water will not be allowed to pass through the caulking. This makes it so that the water is not given a chance to saturate the air. 

Seasonal Humidity

Humidity has been proven to be higher inside than outside, but that is mostly true in warmer seasons. It is mostly true because, in winter months, there is still typically worse ventilation inside than outside. 

Though as we mentioned above, air conditioners give out more water to the air, which increases the concentration of water in the air. 

The reason that this makes the humidity so high is the fact that evaporation is not given a chance to take place. Humidity is allowed to progress at rapid speeds as temperatures are high. The thing with air conditioners is they are meant to lower the temperature

Since air conditioners lower the temperature, evaporation occurs at very slow rates.

This means that there is an abundance of water vapor left in the air, making relative humidity levels high. 

In the months that tend to be colder, the opposite occurs. Instead of having the air conditioning constantly running, there is typically some form of heat being used. This ultimately increases the temperature of the house. 

With the increased temperature, evaporation can occur at faster rates. This makes it so that there is less water vapor in the air. The decrease in water vapor means that the humidity is lower to the point where it isn’t really felt by anyone. 

The actual humidity level may be higher in this case, but in relative terms, it doesn’t really matter in the winter because it isn’t nearly as annoying as it is in the winter. 

Additional Ways to Lower Humidity Levels in Your Home

Luckily, there are many different ways that you can lower the humidity level in your home. Here are some of the most effective ways to lower the humidity and let you feel more comfortable in your home. 


This is the most obvious option. The purpose of a dehumidifier is to remove water vapor from the air when it is oversaturated. 

If you plan on buying a dehumidifier, it is important to understand that they work best when they are in rooms that are entirely sealed off, including doors and windows. Also, it is a good idea to keep your dehumidifier away from walls and other objects to ensure proper airflow. 

Good Ventilation

If there is a lot of moisture in an area, it could very well be from poor ventilation. The problem with bad ventilation is that the air remains still for too long.

This makes it so that water vapor can be absorbed over time, leaving the room with humidity levels that are too high.

A good way to give a room better ventilation is through the use of fans to get the air moving around, and even just cracking a window can make the ventilation better for a room. 

Humidity Monitor

This will not necessarily take the humidity out of your home, but it will do something that will benefit you. In order to fix your humidity, you have to be sure that humidity is the actual problem. 

Buying a humidity monitor will make it very easy for you to tell if your humidity levels are too high in your home. 


There are a few different benefits of using insulation in your home. One of which is the insulation’s ability to prevent humidity levels from rising too high in your home. 

The idea of insulation is to prevent any unwanted particles from entering your home. This will, in turn, not allow any excess water vapor to enter your home, resulting in your humidity levels lowering, which will make the air in your home feel more comfortable. 

Reconsider Your Carpets

Carpets have been historically infamous for retaining and storing moisture from the air. This is one of many reasons why bathrooms and kitchens never have carpet floors. 

With that being said, a carpet that is placed in a room that typically has high moisture levels will catch that excess water vapor and then store it within itself. 

This water that has been absorbed into the carpet can then be released into the air, which ultimately makes the humidity level of the air increase significantly. 

Is the Humidity Too High Inside Your Home?

There are a couple of obvious signs that just about anyone can feel. These are things like feeling clammy, fog invading the windows, and just an overall atmosphere that is heavy and wet.

This is when your home has humidity that is way too high, but how can you tell if your humidity is just a little too high? 

You can walk around with a humidity detector, but that is not always convenient, nor do many people own humidity detectors. 

Instead of doing something excessive like that, here are a couple of ways that you can tell if your humidity is running a little too high. 

  • Check out your ceiling, are there any wet stains? This is a sure sign of high humidity. 
  • Is your paint or wallpaper starting to peel? That happens when there is too much water vapor constantly in contact with them. 
  • How do you and your family members feel? Constant headaches, shortness of breath, allergy symptoms, and coughing are all common in people who spend too much time in high humidity areas. 
  • Have you noticed any mold or mildew? Mold and mildew are caused primarily by water being in places for an extended period of time. 
  • Is any of your furniture looking discolored? This happens when water vapor turns into liquid water and sits on surfaces for an extended period of time. 
  • Does any of the surfaces in your home feel moist? This is an obvious sign, because water vapor can be in the air and then change to be liquid water, leaving your surfaces such as tables and counters feeling wet. 

Some of these instances make it easier to tell if your home has a high humidity level that isn’t so high that it’s obvious. 

If you notice any of these “symptoms” in your home, it may be a good idea to figure out some ways to lower the humidity levels so that your family as well as any guests are able to feel more comfortable. 

With that being said, here are a few more tips on how to lower the humidity levels in your home. 

Final Thoughts

Humidity levels that are too high can make your living space feel uncomfortable. This is why it is important to make sure that the humidity levels in your home are comfortable for everyone around you. 

The reason behind humidity levels being higher inside than outside is largely due to poor ventilation as well as the use of air conditioners. Poor ventilation makes it so that there is less movement in the air, this allows for water to become saturated into the air. 

In regards to the air conditioner, the machine is partly powered by water and meant to lower the temperature of the room. This means that there is not much evaporation that is allowed to occur, making it easier for the water to become saturated in the air. 

If you are having any trouble with the humidity levels of your home, you should certainly consider the tips that were mentioned above as they are sure signs to lower the humidity levels and make your living space more comfortable. 

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