Photo of an insulated unfinished wall with a graphic of water drops being crossed out and the caption "Does Insulation control moisture?"

Most homeowners only have to contend with humidity and moisture in their bathrooms and kitchens, but not you. Other rooms in your home fill up with moist, stifling air too. You know this can’t be good for your home in the long run, so you’re looking for solutions. Could insulating your home help possibly with your moisture problem?

Yes, insulating your home can lessen moisture, especially if the insulation includes vapor diffusion retarders. Because insulation decreases heat transfer, it moderates temperatures throughout your home so humidity and moisture will be less likely to develop.

You probably have other questions about treating your excess moisture problem with insulation, such as what the best type of insulation is for the job. In this article, we’ll talk about that and more, so keep reading!

What Causes Moisture In Your Home?

It doesn’t seem to matter what time of year it is, your home always feels humid. Some days, you step outside and the humidity in your home is worse than it is outdoors. You know this is a problem, but you’re not sure why it’s happening.

Here are some leading causes of moisture and humidity in the home.


Have you ever been in a car on a road trip having a long conversation? What happens to the windows in the vehicle? They all fog up, right?

That’s because every time you breathe, you create humidity. Allow us to explain how.

When you inhale, you take in air that contains oxygen. The oxygen goes to your lungs and then moves to your bloodstream. Then, upon exhaling, you release carbon dioxide.

According to Rowan University, when you breathe out, the air you release is also water-saturated. The relative humidity of this air can be up to 100 percent.

Photo from the outside of a car window coated with moisture from the people inside breathing.
It might happen faster in the car, but it’s happening in your house, too.

In smaller spaces, you might notice humidity changes quickly, but in larger rooms, the cooler air in the rest of the room might dispel some of the humidity.

Either way, you have to breathe to stay alive, so this is an unavoidable source of moisture in your home.

High-Heat Activities

Then there are the activities you do in your day-to-day life that contribute to your home’s humidity. We touched on two of them in the intro: bathing in hot water and cooking.

Running your dishwasher or hand-washing your dishes in hot water can also contribute to the moisture in the air. You can’t forego these activities, but we’ll present some solutions for reducing the associated humidity later in this article.  


Is your house filled to the brim with plants? Houseplants undergo evapotranspiration, which makes for a more humid home.

During this process, water trapped within the plant’s soil travels through the plant’s roots, into the stems, and then out of the leaves. The leaves are technically transpiring when this occurs.

Then, the water on the leaf’s surface evaporates via the leaf’s stomata or pores. The moisture enters the air and evapotranspiration is done.

Moving your plants outdoors, switching to fake plants, or spreading out your live plants throughout the home might help reduce humidity in your home.

Damp Crawlspace & Basement Soil

The foundation of your home can also make it moister than most. If the soil beneath your crawlspace or basement is damp or wet for prolonged periods, this can affect the rest of your home. Moisture rises, much like heat does, so even if the bottommost level of your home is moist, the upper rooms will become humid as well.

Pipe Leaks

When’s the last time you’ve gotten your pipes checked? If one or more of your plumbing pipes have leaked, that could be why your home is moister than it once was. Also, cold pipes are like a magnet for warm air. Condensation then forms on the cold pipes, enough so that they can start dripping. This condensation can also induce moisture.

Does Insulation Help With Moisture & Humidity In A Home?

Your home has all the telltale signs of excess moisture, from condensation on the windows to wall discoloration and musty smells (that are probably mold or mildew). You know you must do something about the issue, and you wonder if you should get your home insulated.

Insulation is an appropriate solution for moisture and humidity for several reasons.

To start, insulation can create an airtight barrier that your home was probably lacking. Without an airtight barrier, outdoor air currents can travel into the house, creating warm, moist conditions. Once you insulate your home, it will feel drier, but in a good way.

Insulation might include a vapor diffusion retarder, a type of material that prevents water vapor from passing through. The insulation will stop moist air at the source, such as your basement, so it can’t rise into the other rooms of your home.

Yet another way that insulation prevents moisture is in controlling temperatures. If your home is uniformly cool, then when you engage in high-heat activities such as washing the dishes or taking a shower, that extra dose of humidity isn’t likely to make the whole house hot.

Photo of a woman's head, shoulders and hands from the back in a hot and steamy shower that's putting lots of moisture into the air.
Giving up showering is one option, but we don’t recommend it.

What’s The Best Type Of Insulation For Moisture Control?

You hadn’t realized there were so many types of insulation out there, everything from spray foam to batts. You also weren’t aware of the multitude of insulation materials. You want the type of insulation that will best rid your home of moisture. Which insulation is that?

For high humidity and moisture, we’d recommend vapor barriers.

Vapor barrier insulation comprises a film-like polyethylene layer that acts as a water retarder. Unlike most types of insulation, which are measured by their R-value, vapor barriers are gauged by water vapor permeability.

So what is water vapor permeability?

Water vapor permeability is the amount of vapor that travels during regular conditions of atmospheric pressure across a surface area. It’s calculated in nanograms of water per Pascal, per square meter, or per second.

In the United States, the International Residential Code or IRC divides water vapor retarders into one of three classes.

Class I water vapor retarders have the least amount of water vapor permeability, with an average rating of 0.1 perms or under. This type of insulation usually includes unperforated aluminum foil or sheet Visqueen or polyethylene.

Class II water vapor retarders have moderately more water vapor permeability, but not by a high degree. Their average rating exceeds 0.1 perms but is no higher than 1.0 perms. For instance, if insulation batts have kraft paper facing, this counts as a Class II water vapor retarder.

The third class has medium-level water vapor permeability. The max number of perms is 10 perms for Class III water vapor retarders.

Since fiberglass doesn’t hold water, nor does it absorb it, this is an insulation material you might use in conjunction with your vapor barrier. Fiberglass won’t develop mold, and it might be able to augment moisture reduction.

The Risks Of Excess Moisture In Your Home

If your home has an accumulation of moist, hot air, it’s not an ignorable issue. Here’s what could happen if you don’t take care of the problem.

More Indoor Air Pollutants

Air pollutants tend to excel in humid environments, which can explain your uptick in dust mites. It’s also harder to breathe when the air is humid. Your lungs’ nerves are under duress due to the hot air narrowing your airways.

If you have a breathing condition such as asthma, humidity can worsen it.

Photo of a man with a distressed face coughing into one hand with the other on his chest. Moisture problems can aggravate asthma and allergies.
Controlling moisture in your home helps control conditions like asthma and allergies.

Mold & Mildew

Humidity is one half of the recipe that fungi like mold and mildew need to thrive. The other half is a dark environment, which might be why your basement, closets, and other hidden surfaces begin to turn black, white, or green with mold.

Mold can aggravate asthma, but even those without breathing conditions will still find themselves coughing and feeling congested.

Higher Utility Bills

The more humid your home is, the more inclined you are to crank up your air conditioning. Your AC usually gets a break in the autumn and winter months, but you sometimes find yourself running your air conditioner during these periods, too.

You pay for it with higher utility bills. You’re also straining your air conditioning unit, so it’s likely to wear out sooner.

Tips For Controlling Moisture In Your Home

Insulating your home with a water vapor retarder or fiberglass is a good start, but it might not be enough to reduce the moisture in your home. Since insulation doesn’t work as well when it’s wet, you need to do what you can to lessen humidity and moisture.

Here are our tips.

Call A Pro To Check For Pipe Leaks

Pipe leaks are not only detrimental in that they increase the amount of moisture in your home, but they’re also costing you money each month with higher water bills.

If after installing insulation, your home is still quite moist, it’s not a bad idea to call out a plumber to assess the state of your pipes. Should the plumber find a leak in one or more of the pipes, get the pipes repaired or even replaced.

Reseal Your Weatherstripping & Caulk

When was the last time you’ve done anything with your weatherstripping? Have you gone through your home recently to look for openings and then caulk them shut?

If it’s been forever since you’ve done these tasks, it’s time to prioritize both. Gaps throughout your home can let in warm air, which makes the rooms feel even hotter. To add insult to injury, critters such as insects and even mice or snakes (if they’re native to your area) can slither their way in through the openings.

Seal them up, stat!

Photo of hands holding a caulk gun, sealing the interior framing of a window against excess moisture.
Caulking and weatherstripping need to be freshened up from time to time to stay effective at sealing out moisture.


As you work to determine the source of the high humidity in your home, buying a couple of dehumidifiers for the most offensive rooms isn’t a bad idea. The dehumidifier will pull the moisture from the air.

Make sure you don’t run the dehumidifier for too long. When the air is very dry, it’s not much better to breathe in than the moist air you’re fighting. Your skin and sinuses can dry out, leading to cracked skin and nosebleeds.

Install Exhaust Fans

If your kitchen or bathroom lacks an exhaust fan, these spaces will feel even more humid. Mold and mildew are risks as well, as warm spaces are the favorites of these fungi. A couple of exhaust fans in the bathroom and the kitchen will make a huge difference in the level of moisture in your home.

Upgrade Your Windows

Buying energy-efficient double-paned or triple-paned windows is yet another measure you can take to combat humidity. The built-in insulating qualities of these windows can protect the interior window glass from freezing cold temperatures that can cause fogging and condensation.


If excess humidity and moisture in your home make your daily life uncomfortable, insulation such as water vapor barriers and fiberglass can help. You must do your part too, such as making small lifestyle changes. Make sure you check up on the health of your plumbing as well!

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