If you’re here because you wanted to know what causes high humidity in a house, the answer is sure to disappoint you. Basically, everything you can possibly do in your home will increase the humidity levels. Cooking, showering, even breathing adds to it. Don’t worry — I’m about to tell you everything about the symptoms you’ll want to look out for.

In the following article, I’ll go over all of the things that can cause a spike in humidity. Furthermore, I’ll also tell you how you can figure out whether that’s something you should be worried about at all, based on the evidence and your own health symptoms. As you can imagine, inhaling humid air for weeks and months at a time does come with some health risks. But before we discuss the causes of humidity and ways to fix it, let’s begin by explaining how high is too high.

Humidity: How High Is Too High?

As I have previously explained in my article on the ideal humidity in a house, that number does depend on the local climate. Typically, the most comfortable range is between 40–50%, or even 30–60%, by some estimates. Anything lower or higher than that is usually pretty uncomfortable. However, there are some significant caveats to even that claim.

For one, the relative humidity should actually be lower than 40% during the winter months, since anything higher could lead to condensation on the windows. Furthermore, there are also areas and climates where the humidity is naturally high.

For example, warmer climates, as well as areas with a lot of rainfall or ones that are close to the sea or the ocean, are usually steamier. So if your hygrometer is showing high percentages, and you live in areas such as Florida or the wetlands of Louisiana, there may not be that much you could do. Still, there are several tips you can follow to reduce the humidity in the winter or summer months.

Even using air conditioning units might affect the humidity inside your home. Specifically, older units do a pretty good job of acting as dehumidifiers, but newer models may potentially make the problem worse. Actually, if you live in a particularly warm climate, you can always use a dehumidifier to cool your home instead of an AC unit. After all, in addition to keeping your air tolerably dry, a dehumidifier should also keep it cool.

What Causes Humidity in a House?

As we have already established, humidity is often influenced by the geographic location and the accompanying climate. However, there are many things that can cause your home to become stuffier. In fact, as I have previously mentioned, doing pretty much everything releases condensation, including exercise and breathing. So let’s talk about this “everything” — what are some of the other everyday activities that can cause that percentage on the hygrometer to climb?


Yes, showers can indeed worsen the humidity levels in your home. It should be kind of a given: if you steam up your bathroom, all of that condensation has to go somewhere. If you open the door after exiting the shower, you’ll release it into the rest of your home. On the other hand, if you keep the door shut, the vapors will have to escape either through the air vents or through a window.

In fact, simply opening the window will go a long way to release the moisture from your house. It may not take care of the whole problem, especially if you’re dealing with serious water damage, but it should help. Speaking of water damage, that’s another way showers can make a bad situation worse.

For example, I once lived in a place where the bathroom and the bedroom shared a wall. More specifically, the bathtub/shower was up against that shared wall. Eventually, the bathroom tiles loosened and started letting water through. So every time I took a shower, the water stain on the other side of the wall widened.

Personally, I didn’t experience any health issues as a consequence of that problem. After all, I know how to dry out a wall after water damage — so I dealt with it as soon as I waterproofed the bathroom tiles with silicone caulk. Still, while that wall dried, it released a lot of that moisture into the air.


If taking hot showers is a risk factor, then so is cooking or even using an electric kettle. I know: you’d think that our homes would be able to deal with a bit of boiling water, but no. In fact, that’s exactly why we have exhaust hoods over the stove in most modern kitchens. Even before we figured out a way to funnel the steam away with fans and pipes, we still had windows.

That steam rising from your stove can cause some real damage, trust me. I’ve had it stain and peel the paint off my walls, and it can often grease up the surrounding shelves and cabinets. Suffice it to say, if you’re trying to keep the amount of moisture in the air low for whatever reason, you’ll want to avoid cooking. Otherwise, either keep the kitchen well-ventilated or get takeout.

Drying Your Laundry Inside

Since we’ve already been to the bathroom and the kitchen, the only room with a water source we’re left with is the laundry room. Assuming that you’re washing and drying your clothes in your own home, you’ll need to find a place to dry it.

Most of us dry our laundry on indoor clothes drying racks throughout the year, not just in the winter months. There are so many reasons to do it that way. For one, keeping them outside might cause the colors to fade more quickly. However, if you’re looking to avoid humidity, you’ll definitely want to use an outdoor clothesline.

When you take your laundry out of the washing machine, there’s still half a gallon of water inside it. All of that water has to go somewhere. If you’re drying your clothes indoors, it will go into the air. Therefore, it’s best to move the laundry outside, especially if it’s not raining.

If you don’t already have a clothesline in your backyard or on the balcony, you can easily set one up. If you’re working with two walls that are parallel to each other, you can use one of these retractable clotheslines. But if you need it to be freestanding, you can use foldable drying racks like this one or this one.

Gas/Propane Heaters

If you’re looking to avoid having your windows fog up during winter, you’ll need to keep the air relatively dry. As I’ve said, it needs to be below 40% in order to keep your windows clear. In fact, there are some tricks you can use to prevent condensation from gathering on your windows overnight. However, you also need to keep warm at the same time.

Still, you should know that of all the space heaters you might use, gas or propane ones are the worst offenders when it comes to humidity. Because these heaters have to burn gas to produce heat, they release a lot of pollutants and steam into the air. While some gas heaters do have a chimney of sorts that takes the exhaust outside, some of them don’t. So if that’s the kind of machine you’re using, I recommend getting another kind of heater as soon as possible.

Leaks in the Walls

As I’ve already mentioned, having water damage on your walls for prolonged periods of time can get problematic. Back in that apartment with the shared wall between the bathroom and the bedroom, I lived with the ever-expanding damp spot on my wall for weeks before I even noticed it.

The stain kept drying during the day and getting bigger after I’d take my shower at night. Had I not fixed the damage when I did, it may have lead to the development of mold — which never bodes well for the lungs. That’s why you need to look out for porous walls, leaks, and rising damp, which can all cause spikes in the hygrometer readings.

Ventilation and Air Conditioning

Your ventilation and air conditioning systems set the quality of the air you have at home. If something is blocking your vents, it could cause a build-up of moisture, which is a breeding ground for many organic and chemical pollutants. That’s why you should maintain your ventilation system — and the same goes for your AC.

As I’ve previously stated, older air conditioning unit models are typically great at wicking moisture out of the air. In fact, they’re so good that it can often become a problem. People who work in spaces that are mostly air-conditioned with no fresh air can have dry and itchy eyes and skin as well as difficulty breathing.

However, even those older moisture-wicking AC units can cause the air to be humid. Usually, that happens because something is wrong with the internal structure with the machine. Most of the time, you’ll just need to change the filters to get it to work right.

Additionally, newer AC models don’t need to work for long periods of time in order to achieve the desired temperature. That means that they don’t have time to dry out your air — which is good if that’s not something you need. However, if you do need a dehumidifying unit, stick to your old one.

Some Plants

Obviously, keeping a potted plant or two in your living room probably won’t increase the humidity levels in your home. However, having 15 of them might. Just think about it: every time you water the soil, some of the water is bound to evaporate into the air before the plant’s roots can absorb it.

Furthermore, some plants naturally release more moisture than others. Steer clear of Ginger, Ficus Benjamin, Areca and Bamboo palms, Asplundia, and Monstera plants if you want to decrease humidity.

Home Renovations

Doing home renovations can make the air more humid if they’re not done properly. Each layer of plaster and paint needs to be dry and cured before another one is applied. So give them a chance to dry completely before you put all of your furniture back where it was. If you don’t, they may release moisture into the air for much longer than they would have if you had properly aired out the room in question while the paint or plaster was damp.

Mold on the wall.

Telltale Signs of High Humidity

If you don’t have a hygrometer, how could you determine the humidity levels in your home? Well, there are some indicators you won’t miss, such as:

  • Wet spots on the walls around faucets and other water sources
  • Peeling wall paint — even if your wall paint is lifting for no apparent reason
  • Bugs, mold, and mildew thrive in homes where the humidity is higher than 80%
  • Corroded electronics

However, outside of the damage you might see on your possessions, you might also deal with some unpleasant health symptoms. So let’s talk about what you can expect if you continue breathing air that’s too humid for comfort for prolonged periods of time.

Symptoms to Be on a Lookout For

There are 3 major symptoms that may indicate that you’re inhaling excess moisture. One of them is that you’re having trouble sleeping. Typically, high levels of humidity in the air can cause it to feel stuffy and overheated. Since humans get their best shut-eye in relatively cool environments, it’s no wonder that humid air makes us toss and turn.

Because high humidity makes us feel overheated, we inevitably start to sweat in order to regulate our body temperatures. However, that means that we’re losing water, which means that we can start to feel dehydrated. That comes with a host of other problems, including fatigue, fainting, cramps, and ultimately — heat stroke.

Finally, an increase in humidity levels can also be dangerous to people who are prone to allergies. As I have previously mentioned, dust mites and mold spores thrive in humid environments. Those are the very things people with allergies would have potentially fatal reactions to.

How to Lower the Humidity in a House

Fortunately, there are ways to decrease the level of moisture in the air. Obviously, one of the most effective solutions would be to use a dehumidifier that can prevent or treat mold. Alternately, if you’re worried about the amount of noise these machines make, you can get a quieter model. However, if your problems with humidity are a one-off thing, it may not make sense to purchase a machine to deal with it.

There are ways to remove the moisture without a dehumidifier. For example, natural solutions include:

  • Moisture-wicking plants such as Xerophytes, Epiphytes, Tillandsia, Peace Lily flowers, Reed Palms, English Ivy, and others
  • Silica gel — you can leave some gel packets in the kitchen or the bathroom
  • Activated charcoal bags (like these) — which will absorb both the odor and the moisture

You can also decrease your own impact on the humidity by moving your clothes drying rack and some of your plants outside. And remember: ventilation is key.

Final Thoughts on Causes of Humidity

Hopefully, you now understand the consequences of allowing the humidity levels in your house to rise past a reasonable point. If your hygrometer readings have been steadily climbing over a period of days or weeks, ask yourself whether you are doing anything to contribute to the excess moisture in the air.

If you are — don’t worry. There are many ways to wick moisture from our surroundings! You can start by lowering the temperature of your showers and opening the window while you cook. Remember, many unwanted organisms thrive in humid conditions, so let’s not invite those into our homes, if at all possible.

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