Why Is My Room So Humid?

Let’s not mince words here; it totally sucks when your room is way too humid. Aside from making it much harder to get comfortable and relax, an excessively humid environment can cause damage to your home and even a variety of health problems.

As for why your room might feel unnaturally humid, there are a few possible reasons for this. The outside climate plays the biggest role in affecting indoor humidity, but excessive humidity might also be caused by water leaking into your home, an oversized A/C unit, or overusing appliances that use water.

In this article, we’ll explain more about humidity in general and the reasons your room might be feeling so humid. We’ll also show you the signs you should look for to determine if your home is too humid, and what you can do to deal with high humidity in your home.

Humidity Explained

Since the outside climate has the greatest effect on indoor humidity, let’s quickly explain how humidity works and how exactly the climate affects humidity.

The biggest factor that affects how much humidity can be present in a specific area is the temperature of the outside air. Warm air can hold more moisture, while cold air can hold less moisture.

The amount of moisture in the air compared to how much moisture could possibly be in the air based on its temperature is called “relative humidity”. 

The relative humidity is what is usually used when it comes to measuring humidity, since the total amount of humidity that can exist in the air is always in flux due to changing temperatures.

The right amount of relative humidity for an indoor space is generally considered to be between 30-50% (that is, the air should contain no less than 30% of its maximum possible moisture content and no more than 50%).

Reasons Your Room Is Too Humid

If your room feels excessively humid, there could be a few reasons why. The outside climate is probably the most likely reason, but there are a few other potential reasons also. Let’s go over each of these reasons now.

Outside Climate

As we’ve mentioned a few times now, the climate outside is ultimately going to be the biggest factor that affects the humidity inside your home. If you live, for example, somewhere in the southern U.S., the climate is naturally going to be a lot more humid and the humidity in your home will be affected similarly.

Related: Does Outdoor Humidity Affect Indoor Humidity?

If you live in such an area, one of the best things to do is to make sure your home is as weathertight as possible. We’ll talk a little bit more about how to do that later on.

Water Leaking Inside

The high humidity in your home might also be caused by water leaking into your house from somewhere. The source of this leak could be corroded plumbing or a small hole in your roof.

It may also be coming from under your foundation if you have inadequate grading. When designing the foundation for a house, the land around the foundation is usually graded; that is, a slope is constructed leading away from the house to keep rainwater and melted snow away from the foundation.

If water that accumulates around your house can’t be drained properly, it can start to seep in from under your foundation, which can cause high levels of humidity and potentially even damage your home.

Oversized A/C Unit

You might be confused as to why having an oversized A/C unit for your home will actually increase your indoor humidity levels. After all, an A/C works by removing the moisture from the air along with the heat, so wouldn’t a larger A/C unit be able to remove more moisture?

portable air conditioner

Logically this makes sense, but in practice not so much. A/C units are designed to shut themselves off when the interior temperature is cool enough, and start up again when the interior temperature climbs above a certain threshold. Since a larger A/C unit can cool an enclosed space more quickly, it will cycle on and off more frequently.

This quick cycling is where the problem lies. Air conditioners contain a component called an evaporator coil, which removes moisture from the air. However, the evaporator coil can only work properly when the air conditioner runs for long enough.

This means that with an oversized A/C unit that frequently starts and stops itself, the evaporator coil doesn’t have the time to actually remove any of the moisture from the room. So an oversized A/C unit might cool your home more quickly, but won’t actually make it any less humid.  

Overuse of Showers and Other Appliances

If you’re the type who prefers to take long, steamy showers, then you may unfortunately be the reason why your home is so humid. As you can imagine, showering for a long time will increase the amount of moisture in your house’s air by quite a lot, and that moisture can linger for longer than you might think.

Overusing other appliances can also drive the humidity levels in your house way up. In particular, anything that uses water like washing machines, dishwashers, and some cooking appliances can increase your indoor humidity levels.

What Are the Signs of Excessive Humidity?

It’s usually pretty easy to tell if your home is too humid; as we’ll explain, there are several telltale sights and smells you should look out for. Let’s go over these signs of high humidity now.

The Smell of Mildew

The smell of mildew is a prime indicator that the humidity levels in your home are too high. Mildew loves to grow in warm, moist conditions, which is why you’ll often find mildew in basements, bathrooms, crawlspaces, and other parts of your home where these conditions can be found.

Mildew has a pretty distinctive odor, and you’ll know it if you smell it. It usually has a smell similar to that of rotting wood or damp socks.

Presence of Mold

If you actually see mold growing inside your house, that’s an even more obvious sign that your house is way too humid. It’s pretty common to find mold growing in your shower or basement, but if you ignore it for too long it can turn into a serious problem.

In addition to being smelly and gross, large mold colonies in your home can cause a bunch of health problems. Itchy eyes, a stuffy nose, wheezing breath and a chronic cough are all symptoms of exposure to mold, and the longer the exposure lasts the worse these symptoms tend to get.

Condensation on Various Surfaces

If the humidity levels in your home are too high, you’ll start to notice condensation appearing on some of your interior surfaces. In particular, you’ll notice it on pipes, windows, mirrors, or other surfaces that tend to be a little cooler than the surrounding air.

Warped and Discolored Wood

Wood really doesn’t do well when it’s exposed to moisture for a long period of time. Wood likes to absorb lots of moisture, which causes it to swell up. This can cause wooden surfaces like floors and windowframes to become warped and lumpy.

If enough time passes, the wood will start to rot. If you notice weird spots and discolored patches on the wooden surfaces in your home where there weren’t any before, this is a sign that your wood has begun rotting, probably due to excessive moisture.

Allergy Symptoms

High levels of humidity can worsen allergy symptoms in a few ways. They promote the growth of mold, of course, and they also promote the growth of dust mites, which cause similar allergy symptoms.

For people with asthma, high humidity just on its own can make it a lot more difficult to breathe. In any case, you’re going to be a lot less comfortable if you spend too much time in an excessively humid home.

How to Reduce the Humidity in Your Room

If you are finding that your home is way too humid, there are a few things you can do to help. Here’s what you should try:

Make Sure Your Home Is Sufficiently Insulated and Ventilated

We mentioned earlier that weatherproofing your home can help keep the humidity levels in your home at reasonable levels. In order to properly weatherproof your home, you need to make sure that it has enough insulation and that the spaces around your doors and windows are properly sealed.

Related: Why Is the Humidity in My House So High After It Rains?

All of this will help keep the interior temperature of your home at a more consistent level, and also keep more humidity out. You should also make sure you have a decent amount of ventilation in your home, particularly for areas like the bathroom, basement, and kitchen that tend to be a bit more moist.

Run Your A/C 

Since your A/C works by removing some of the moisture from the air, you can use it to reduce the humidity in your home. It’s important, however, to make sure that your A/C unit is actually the right size for the area you have, otherwise it won’t work as well as it could.

Invest in a Dehumidifier

While an A/C unit will remove some of the humidity from your house, a dehumidifier is the best way to eliminate humidity from an enclosed area. A dehumidifier won’t cool your home like an A/C unit, but it’ll do a much better job of dealing with humidity.

Related: What Size Dehumidifier Do I Need For My Crawl Space?

When using a dehumidifier, you have a couple of choices; you can use a portable dehumidifier or a whole-house dehumidifier.

Portable dehumidifiers are cheaper and can be moved around, but can only remove the humidity from one room at a time. Whole-house dehumidifiers are much more expensive and usually have to be installed in a fixed location, but as their name implies, they can remove the humidity from your whole house.