Does your house feel like a sauna during the hot summer months? Are you wondering, “why is my house so humid”? This article will help you explore the causes of high humidity levels in U.S. homes, and ways to tackle the problem. 

And tackle you must. High humidity in your home can be quite problematic.

Not only does the heavy, moist air make your living uncomfortable, but it can also lead to mold growth, poor indoor air quality, and wood rot. And, serious health issues such as skin and respiratory problems.   

So, why is my house so humid, you’ll ask? There could be many causes for your home’s high humidity. Based on the specific problem, you could fix the issue and make your house feel comfortable as well as smell fresh all year round.

What is indoor humidity? 

measure humidity

Indoor humidity refers to the amount of moisture or water vapor in the air inside a building. Humidity is typically measured using a device called a hygrometer.

Maintaining the right indoor humidity level is crucial for comfort, health, and the well-being of your home. So, why is my house so humid, you’ll ask? There could be many causes for your home’s high humidity. Based on the specific problem, you could fix the issue and make your house feel comfortable as well as smell fresh all year round.

How humid should my house be?

What constitutes a comfortable humidity level in your home varies from person to person. Keep in mind that your personal preferences and the climate you live in play a significant role in this. In hotter, more humid regions, you may find lower humidity levels more appealing to maintain a refreshing and pleasant environment. Energy Star and experts suggest that the optimal humidity level for most individuals falls within the 30% to 50% range. While this may seem relatively high, outdoor humidity levels can be considerably higher.

What are the symptoms of excessive humidity in your house?

signs of humid house

While we understand that you can’t keep measuring the humidity levels in your home with a humidity or dew meter, there are some important telltale signs that indicate that the humidity is too high inside your home. These could include clammy skin, visible moisture buildup, foggy windows, and a heavier atmosphere. Perhaps a musty odor, dust mites, or the smell of mold and mildew.

Here are some of the signs you can watch out for. 

  • Visible condensation on cooler surfaces such as windows, room mirrors, plumbing pipes, and in your basement area. If you spot any of these, check the surrounding area to see if the moisture spreads to the walls.
  • Wet stains on the ceiling, dark spots, discoloration on the walls, or crumbly stucco. 
  • Peeling paint or creaking floorboards.
  • Continuous headaches, shortness of breath, frequent allergy symptoms such as wheezing, or chronic cough.
  • A distinct odor of mold and mildew.

If you experience any of the above symptoms, you should have your home thoroughly checked.

Read more: Condensation spots on walls

Why is my house so humid?

Several factors contribute to your home’s humidity. Apart from the obvious effects of the surrounding climate and temperature, you’ll also have to consider the house design, its construction, and the building materials, the use of a vapor retarder, the home’s insulation, and how airtight the property is.

Then, there are other factors such as an ineffective (too large or too small) air conditioner capacity or oversized windows that you must consider. Let’s explore all the reasons below.

The local climate

condensation in windows

Climate can directly affect the humidity in a house. It’s likely to be musty inside a residence if the outside air is unusually humid. The primary cause of an uncomfortable living atmosphere and a key contributor to high humidity levels in your home are the changing seasons and temperature fluctuations.

Poor ventilation system

ventilation in house and humidity

A sound ventilation system and air circulation can help control a home’s humidity, structural integrity, and health. Also remember that everyday activities such as cooking, running the dishwasher, and long hot showers can affect humidity levels – naturally adding excessive moisture to the air. The solution to this problem is to keep moisture-prone areas such as bathrooms and kitchens well-ventilated by opening a window or installing an exhaust fan. You can hire a professional who will direct your home appliances, such as clothes dryers and stoves, to vent outside of the home.

Plumbing leaks

drain trap maintenance

A leak in the plumbing system – either from a bathroom sink or a kitchen sink – can increase the moisture in the air. It’s important that you regularly check the plumbing pipes for any cracks, leaks, or corrosion.Finding and dealing with a plumbing leak in the early stages could help you prevent serious water damage, musty smells, and potential mold growth.

Read more: Old house plumbing

Moisture from the soil beneath your home

Are ants a problem in vegetable garden

The soil underneath your home’s foundation can penetrate inside your home as rising damp. The reason could be ineffective yard grading that allows groundwater or excessive rain to accumulate near your home’s foundation. Poorly insulated basements can make the issue worse.

To prevent this problem, ensure good yard grading and remember to clean your rain gutters and downspouts correctly and regularly. You may even consider installing awnings above your windows and doors to keep the water out.

Read more: How to remove old gutter sealant

Your HVAC system may be inappropriate

An oversized AC unit may be the reason for the excessive moisture inside your house. The evaporator coil inside an air conditioner acts as a dehumidifier and pulls humidity from the air. However, if the air conditioning system is too large, it may cool a room too quickly. It will not have sufficient runtime to dehumidify your home properly. Therefore, it’s always a good idea to consult an HVAC technician before installing a cooling or heating system in your home.

How to control high humidity levels in your house?

You have two choices when it comes to controlling humidity at home – one for the short term and the other for the long term.

For the short term, you can use a portable air conditioner or dehumidifier to reduce indoor humidity. These machines work well at making your home less humid, but only when they’re running. When you turn them off, the humidity starts to come back, and you’ll also need to empty the dehumidifier’s water container every few hours, which can be a bit of a hassle.

If you’re looking for a long-term solution, consider upgrading your HVAC system and making sure your home is well-sealed and insulated. It might seem like a significant investment, but it will pay off in terms of comfort and energy savings. A properly sized and installed HVAC system will keep your home at the right humidity levels and temperatures throughout the year, especially if your house is sealed and insulated properly.

Key takeaway

Now you know the answer to “Why is my house so humid in summer?”. Several things can make your home feel very humid. It can happen because of the weather outside, water from the ground, or steam from appliances, cooking, showers, and bathrooms. Too much humidity can create issues such as mold, condensation on windows, and water damage on your walls.

Excessive humidity in your home isn’t just uncomfortable and damaging – it can even be bad for your health. In the worst case, it can lead to serious respiratory issues.

So, it’s important to keep the right level of humidity inside your home. You can do this by improving how air moves through your home, adding insulation, and making sure your heating system is working well. You might also want to use a dehumidifier or an AC system to remove moisture from the air.

Why is my house so humid? Let’s solve the mystery, now! was last modified: September 4th, 2023 by Ramona Sinha
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