
Protected: Testing For Mold? Avoid ERMI

Do you need to reduce humidity in your home?
Don’t wait to address a water leak or excess humidity. The clock is ticking. Every hour that passes after a water leak— or excessive humidity builds up — means you’re getting closer and closer to a mold problem.
Discover how long you have to fix the issue and 3 simple ways to reduce humidity in your home.
The industry standards for water damage and mold removal state that you need to take action in the first 24-48 hours to prevent your moisture problem from becoming a mold problem.
Why?
Mold spores are ubiquitous. They are found everywhere, in every climate, and every place. Mold spores make their way into your home in many ways. A gentle breeze carries them in from open windows, and spores can hitch a ride right in your front door on the bottom of shoes or on your pet’s fur.
Mold spores are everywhere.
But mold spores don’t become a mold problem until excess moisture comes into play.
“Once fungi are inside,” says the World Health Organization, “growth can only occur in the presence of moisture.”
Moving quickly to control moisture in your home is essential for preventing a mold problem.
These three steps can help you reduce indoor humidity.
Before you can start reducing the amount of moisture in your home, you’ll need to identify and control the source.
While this sounds like a job for a professional, fear not. With a little sleuthing (and a few affordable tools), you can most likely find the source of a water leak or excess humidity all on your own.
You can use a hygrometer to measure the humidity in various home areas. Everyday tasks such as cooking, cleaning, and laundry can contribute to increased humidity levels, so check kitchens, bathrooms, and laundry areas.
Infrared cameras and water sensors can help you determine if an unseen water leak is causing humidity to build up inside your home.
Now that you’ve stopped the excess moisture from coming into your home, it’s time to remove the moisture built up inside.
When it comes to ventilation, your first instinct may be to throw your windows wide open. But, depending on your climate, opening a window may do more harm than good. If you live in a particularly humid environment or it is the middle of the rainy season, opening a window could allow excess humidity to enter your home, exacerbating your moisture problem even further.
The best way to ventilate your home is to run exhaust fans in kitchens, laundry rooms, and bathrooms.
That’s right: exhaust fans aren’t just used for removing foul odors from these parts of the house!
When you start cooking, running a shower, or doing a load of laundry, a properly functioning exhaust fan will vent the moisture out of the home.
A note of caution, however.
In order to properly ventilate moisture and reduce humidity, all exhaust vents must vent moisture outdoors, not send moisture into the attic or wall cavities.
If your exhaust vents are just sending moisture to other parts of the house, they will only make your moisture problems more severe and possibly aggravate mold growth in hard-to-reach areas.
If you have utilized your home’s exhaust fans and your moisture meters and other tools are still alerting you to excess humidity levels, it may be time to try a dehumidifier.
Dehumidifiers range from portable units to whole-house add-ons for HVAC systems. They work by removing moisture from the air and collecting it in a tank.
Dehumidifiers should be set at the lowest setting for maximum effectiveness. You can find models with automatic drainage functions so you don’t have to constantly empty the water collection tanks. Most will empty the moisture via a straw which will deposit the water down a floor drain.
Pro Tip: Use humidity gauges and dehumidifiers in tandem for maximum effectiveness. Set alerts and utilize mobile apps and automatic settings to ensure your home remains at the ideal indoor levels of humidity: between 40% and 60%.
Check out the Consumer Reports Dehumidifier Buying Guide to get dehumidifier ratings for some of the most popular brands.
Did you know that air conditioning units aren’t just for cooling your home? HVAC systems can also be used for dehumidifying. While it is bringing down your home’s temperature, a properly functioning (and properly sized) AC unit can also remove excess moisture from the air.
When it comes to using a window air conditioning unit for dehumidifying, bigger is not always better. Significant mold growth can often be found on the insulation in air conditioning units. This is fairly common when units are oversized, which causes the unit to cycle on and off. During this process, condensation can develop on the insulation, and sometimes the coils, inside.
Running an AC unit on a lower setting and avoiding the cycle-on, cycle-off process can help prevent mold growth due to condensation buildup. Alternatively, a smaller unit that’s a better fit for the room is a better buy than a too-large unit.
How big should your window unit be? Check out this calculator to find the right size air conditioner for your room.
What happens if you don’t get your moisture problem under control? Read our Complete Guide to Humidity and Moisture in the Home to get more information on ways to prevent and control the moisture issues that can quickly turn to mold problems at home.
Can you measure indoor humidity levels and find water leaks on your own, or do you need a professional to do the job?
There’s no need to guess when it comes to how much moisture is in your home. You can use tools to monitor your indoor humidity levels and find water leaks — and you can easily find them at local hardware stores and online.
Before we get into tools that measure humidity and moisture in your home, let’s take a moment to talk about the different ways humidity is measured.
Relative Humidity
Relative Humidity (RH) is the amount of water vapor present in the air relative to the amount it could hold at that given temperature.
When air gets warmer, it expands and can hold more water vapor.
When air gets colder, it contracts and can hold less water vapor.
Let’s do a little science experiment in our minds to picture this better:
Imagine a 12-ounce cup filled with 6 ounces of water. This is our control cup. It’s 50% full of water.
Now imagine that it’s a hot day. As the day gets warmer, that cup expands and gets bigger. You now have a cup that could hold 24 ounces of water. This bigger cup is still filled with 6 ounces of water, but now the cup is only 25% full.
Now imagine that it’s a cold day. And the colder it is, the smaller your cup gets. Your cup has shrunk down to a 6-ounce size. If your 6-ounce cup is filled with 6 ounces of water, your cup is 100% full.
All 3 cups held the same amount of water.
But the measurement of water changed relative to how much each cup could hold.
This is how relative humidity is measured. It’s the amount of water vapor the air can hold at any given temperature, and the result is expressed as a percentage.
Absolute Humidity (AH):
Absolute humidity is the actual amount of water vapor present in the air, regardless of the temperature.
Absolute humidity compares the mass of water vapor to the mass of dry air, and it’s expressed as a ratio in grams of moisture per cubic meter of air (g/m3).
Absolute humidity is entirely independent of temperature. It measures how much water vapor is in the air, regardless of the temperature.
Usually, when we’re talking about ideal humidity levels (between 40% and 60%), we’re talking about measuring and monitoring relative humidity (RH) levels. You can learn more about humidity — and the problems it can cause — at our Complete Guide to Humidity and Moisture in the Home!
Now, on to the tools!
A hygrometer is a tool used to measure the amount of water vapor (humidity) in the air. Remember when we talked about temperature affecting humidity levels above? Your hygrometer will typically measure the relative humidity (RH) of your air and show you the temperature as well as its correlating humidity percentage.
Hygrometers have come a long way from their first designs when inventors used oak husks or human hair to measure humidity! Today’s humidity measuring tools use semiconductive materials or mercury thermometers to precisely measure relative humidity.
Modern hygrometers will usually have a nice, big easy-to-read digital display.
Even better, many digital hygrometers connect to Wi-Fi or Bluetooth and send you text or email alerts when your temperature and moisture levels exceed the pre-set limits. What should your ideal indoor humidity levels be? ASHRAE recommends a target level of 45% RH, but hitting that exactly on the nose can be difficult. It’s easier to set an ideal range of 40-60% humidity.
Monitoring is easy with digital hygrometers that feature apps (for iPhone or Android) that allow you to monitor humidity levels on the go. And it allows you to know when something is off and you need to take action, no matter where you are.
Look for a hygrometer that allows for multiple wireless sensors so you can monitor humidity levels of various locations throughout your home. Most moisture and mold problems occur in your home’s “out of sight, out of mind” places, such as attics, basements, crawl spaces, and other tucked-away places that you don’t often frequent.
Moisture meters are valuable tools to help you detect moisture in building materials such as wood or wallboard. If your home has a water leak in an out-of-sight location, such as behind a wall or ceiling, a moisture meter can help you find it even if you can’t see it.
There are two types of moisture meters; pin-type moisture meters and pinless moisture meters.
Pin-type moisture meters use two electrodes to scan for moisture by inserting the probes into drywall, or whatever material you’re concerned about,. although they are designed and calibrated to measure moisture in wood. Since the device looks for moisture readings between the electrodes, it can only scan a smaller and more precise area. Pin-type meters are typically used in home inspections. Keep in mind that they leave small holes where you probe, so be ready with your spackle if it’s in a visible area. These tend to be the least expensive type, and also the most user friendly.
Pinless moisture meters scan larger areas and make finding moisture readings and leaks a lot quicker. Pinless meters use electromagnetic waves (like radio waves or an electrical current) that are affected by moisture. They can be more difficult to read because different materials have different densities, and varying conductive properties. This type of moisture meter is most often used by professionals, and can get fairly expensive.
The key to using a moisture meter is to take things slow, be prepared for false readings, and always look for the source. Wet materials are a problem, but the real issue is how they got wet in the first place.
Time is of the essence when you have a water leak at home. Often, a water leak can cause damage long before you see a visible sign of the leak.
Place a water sensor in leak-prone areas of your home, such as near:
Some water sensors are Wi-Fi enabled so you can get instantly alerted to a water leak in your home. Others may be configured to shut off the water in the house to prevent a small leak from becoming a big problem.
We recommend: Sensative Strips Drip with 10 years of battery life.
A new tool is now much more accessible for consumers to use at home: infrared cameras.
Infrared camera don’t really “see” through your walls, however, they are really good at measuring surface temperatures. What does this have to do with water leaks? A wet spot will register colder than its dryer surrounding areas because of evaporation. These cameras used to be $50-60k, but tech advances now mean you can get a good one for a few hundred dollars.
They are more advanced, not for every user, but can be incredible for finding leaks, wet or missing insulation, leaky ducts, issues in the ceiling and more.
The key is to use them effectively is to consider an infrared camera a screening tool, and then go on to investigate with moisture meters and other tools to collect more data.
Tools that help you detect water leaks and monitor/measure your indoor humidity levels can help you take control over moisture problems in your home. Excessive moisture can lead to mold growth, structural damage, an increase in pests, and more symptoms that can be harmful to the building and the health of occupants.
Luckily, these tools are easily found online or at your favorite hardware store, and help you take back control of your home’s health and safety.
Are you monitoring humidity levels in your home? Maintaining an ideal humidity range inside your home is more important than you may think. The amount of moisture in the air (humidity) in your home can mean the difference between a healthy home or a home that’s making you sick.
Even without a humidity gauge—known as a hygrometer— to measure the amount of moisture in your air, it can be fairly obvious when you have a humidity issue.
At least, it is if you know what to look for.
These five issues can be directly tied back to excess humidity or a water leak in your home.
A mold problem in your home always originates from a moisture
problem.
Anywhere from 30% to 50% of homes globally have issues with dampness and mold, according to a World Health Organization (WHO) Report on Indoor Air Quality – Dampness and Mold.
Mold spores, which are like microscopic reproductive seeds, are found in the dust and surfaces of every house, including those that don’t have issues with dampness, says WHO.
Mold spores are ubiquitous.
Spores make their way into your home through open windows and doors or by hitching a ride on shoes, clothing, and even pets. And then they wait for the right conditions to thrive.
“Once fungi are indoors,” says the WHO report, “growth can occur only in the presence of moisture.”
Like all living things, mold also needs nutrients to survive. However, your house offers plenty of those in the form of household dust, construction materials, wallpaper, wood, paint, glue, books, and other paper products (to name a few). Modern buildings are made of materials that most molds find delicious, such as drywall, so there’s no shortage of nutrition.
Since removing all fungi food sources from your home is nearly impossible, maintaining ideal humidity levels is critical for preventing mold growth.
Spiders, dust mites, and rats, oh my! The second sign of excess moisture and humidity in your home is an increase in uninvited critters and creepy crawlies.
Critters need moisture to survive, and damp homes offer plenty of water for insects, arachnids, and rodents to drink up.
Not to mention the miniature “circle of life” that occurs once mold becomes a food source for small bugs, which then become a food source for larger bugs and spiders, which, in turn, become a food source for rodents, and so on.
Dust mites in particular love to eat mold! (Researchers have found mold spores in their feces and attribute much of the allergenicity to the unique qualities of this lovely combination.)
They’re not the only critters that like to make mold a meal, either.
Booklice (small, soft-bodied insects) usually eat mold, fungi, and glue from book bindings. In homes, booklice are often found in damp areas and are a clear signal that your home has a mold problem.
And then the spiders come along and eat the booklice. And the rodents eat the spiders. It’s like the nursey rhyme, the Old Lady Who Swallowed a Fly.
The longer the moisture problem, the larger the critters, and the more of them you’ll find. Take away the water and they find somewhere else to party. It’s that simple.
Could respiratory health issues have more to do with poor indoor air quality, due to dampness and mold in your home, than viruses or bacteria? any kind of viral or bacterial infections? Emerging medical research supports this notion.
A pair of studies from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the U.S. Environmental Protection Agency (EPA) estimates that 21 percent of current asthma cases in the U.S. are attributable to dampness and mold exposure.
Of the 21.8 million people reported to have asthma in the U.S., approximately 4.6 million cases are estimated to be attributable to dampness and mold exposure in the home, reports study researchers.
When it comes to predicting asthma, dampness and mold in the home are ranked second only to family history of asthma as a risk factor.
Did you know? Kids who live in a house with a musty “moldy” odor are 2 times more likely to get asthma than kids who don’t.
How does dampness contribute to asthma?
Researchers suggest that it’s not the excess moisture itself that causes asthma issues, rather, it’s that the moisture influences the growth of various microorganisms that leads to respiratory health issues.
In another study on indoor dampness and asthma, researchers suggest that dampness may lead to the development of asthma, exacerbate existing asthma, and that the factors related to dampness that lead to asthma were most likely attributed to the fungi and dust mite allergens.
The most recent evidence from epidemiologic studies and meta-analyses also show indoor dampness or mold to be consistently associated with increased asthma development and exacerbation, dyspnea, wheeze, cough, respiratory infections, bronchitis, allergic rhinitis, eczema, and upper respiratory tract symptoms—in allergic and nonallergic individuals.
A building’s longevity is directly connected to its ability to shed water.
In a Building Moisture and Durability report prepared for the U.S. Department of Housing and Urban Development (HUD), moisture is named as the “single greatest threat to the durability and long-term performance” of homes and buildings.
Excessive exposure to moisture is not only a common cause of significant damage to many types of building components and materials, states the report, but it also can lead to unhealthy indoor living environments.
Some of the more serious effects resulting from moisture problems in houses include:
Why is moisture public enemy #1 when it comes to the durability of your home?
Consider the materials used to build a single-family or multi-family residence.
Most building structures begin with a concrete slab foundation that sits in the surrounding soil. Concrete is made from a mixture of crushed stone and a paste made from water and cement. During the drying and curing process, most of the water from inside the concrete works its way out through tiny highways called capillaries. Unfortunately, these tiny moisture highways are two-way streets. Not only can water work its way out of the concrete, but water can also work its way back in via excess humidity, water leaks, and even excess moisture in the soil around the house. (This is known as capillary action.)
It’s like a giant sponge sitting at the base of your home.
Now consider typical building materials that go on top of that concrete slab foundation, such as wood, gypsum wallboard, fluffy insulating materials, carpet, and carpet padding, to name a few. Like concrete, these materials also act like sponges when it comes to moisture, but, unlike concrete, they also do double-duty as nutrient sources for fungi.
This is why we recommend you don’t finish your basement…until you read this.
Fungi cause considerable damage to buildings, according to the WHO Guidelines for Indoor Air Quality.
Not even the dumbest of the three little pigs ventured to make a home out of paper, yet with drywall at the center of our modern construction process, it is much like building houses out of paper maché.
We essentially build ourselves self-composting homes; just add water. The wood we build with is often young wood, and loaded with sap—it’s a tasty treat to wood-eating bugs such as termites and wood-rotting fungi, to name a few.
And, as we covered above, our building materials are prone to rapid degradation when exposed to moisture.
Too much dampness in a building can erode away building materials, corroding metals, decaying timber, softening and crumbling plaster, and disintegrating bricks, stones, tiles, and flooring.
As damp building materials degrade, they release emissions of volatile organic compounds (VOCs)—including formaldehyde—which can lead to increased indoor air pollution and negative health effects for occupants. The use of potentially hazardous chemicals such as pesticides to target termites and pests or chemical biocides meant to “kill” mold can add even more VOCs to the indoor air, and also leave a toxic residue on surfaces, which can become easily airborne and inhaled.
Nasty stuff.
Worse, structural damage from a moisture problem at home most likely isn’t covered by your insurance policy, either. Most homeowners’ policies are designed to cover structural damage that occurs as a result of a specific event (like a hurricane or explosion), NOT from chronic dampness in your home. Damage that happens gradually—like the settling, shrinking, and cracking of your foundation—is typically excluded by homeowners insurance.
Which means you could be left holding the bill for your structural damage caused by dampness, mold, and termites.
Now that you know that mold, pests, respiratory illnesses, rot, decay, and structural issues are all signs that you have a moisture problem at home, what comes next? Check out our Complete Guide to Moisture and Humidity in the Home to discover what your ideal household humidity level should be and what steps to take to address the moisture problem for a healthier home.
Do you need to be concerned about moisture and mold in your home?
According to the U.S. Department of Housing and Urban Development, moisture is public enemy #1 in your home. Excess humidity levels or water leaks can lead to mold growth, attract pests, increase allergens, cause structural issues through rot and decay, and negatively impact the health of occupants.
Unfortunately, it’s not always easy to see signs of a water leak or humidity issues in your home.
Sure, a flooded basement is obvious.
But not all sources of excess moisture in the home are immediately apparent.
Excess humidity inside your home can be caused by everyday activities such as air-drying laundry, cooking, and showering, to name just a few.
Luckily, your senses can help you identify moisture and mold issues at home. So, when should you worry about moisture or mold?
Visible mold is an obvious example of seeing something that’s not quite right.
While people tend to be concerned about toxic black mold, mold actually comes in a range of colors. Mold often tends to start growing as fuzzy, white fibers. As it develops and reaches maturity, mold will start to look gray, green, or black. It usually grows in a circular pattern but can also grow in patches or streaks.
Dark spots of mold are an easy red flag to notice!
But excess humidity and water leaks also leave other visible signs in their wake.
Condensation is the change of water from its vapor form into liquid form. It generally happens when water vapor in warm air encounters a cool surface (like a window) or pockets of colder gasses.
When the steam from the shower covers your bathroom mirror or your glasses steam up when you lift the lid of a boiling pasta pot, that’s condensation in action.
In your home, condensation on the interior of windows and doors occurs when warm, humid air comes into contact with a cool surface.
As a result, you’ll see water droplets form on window glass, exterior doors, and even down near the ground-level of closets or rooms with exterior walls.
Excess humidity or hidden water leaks will flip a switch on the process of rot and decay, essentially “turning on and turning up” the cycle of destruction for your building materials.
Some of the visible signs of rot and decay due to moisture in your home include:
Any visible sign of degradation of your home (or its building materials) is another red flag of a moisture issue.
Water is life. It makes up the majority of our planet and the majority of our bodies. Plants and animals need it to survive.
Including pests.
When your home has become a source of water, you are likely to notice an increase in the critters in your home, such as:
Have you noticed an increase in creepy crawlies, critters, and pests in and around your home?
It may result from a water leak or excess humidity providing lots of wonderful, life-giving water to the tiny creatures that like to share our spaces.
Does your house smell a little funky?
If your household visitors are wrinkling their noses when they enter your home or if you feel like your house smells like mold, stinky socks, old cheese, or dog farts (hey, you don’t even have a dog!)… your nose might be telling you something.
Microbial volatile organic compounds (mVOCs) are strong-smelling compounds produced by fungi (mold) and bacteria during their metabolic processes.
“Because mVOCs often have strong or unpleasant odors, they can be the source of the ‘moldy odor’ or musty smell frequently associated with mold growth,” says the Environmental Protection Agency (EPA).
“A moldy odor suggests that mold is growing in the building and should be investigated.”
The bad news is: a musty or moldy odor is a giant red flag that you’ve got mold growing somewhere. Furthermore, it’s more than an aesthetic nuisance. It’s also a health hazard, as you will see below.
The good news is: your nose can alert you to the presence of mold even if you can’t visibly see it anywhere.
Why is this good news?
Well, if you smell something, you can do something. Like confirm that you have a mold or moisture problem and take steps to get it fixed.
If you couldn’t see it and couldn’t smell it, the mold growing in some out-of-sight place in your home may be left to run rampant. So thank your nose for doing its job and alerting you that something in your house just isn’t right.
Tip: fix it, don’t cover it! If your house smells funky, musty, or moldy, don’t just cover it up with scented candles, fabric sprays, or plug-in scents. Not only does covering up the smell not fix the problem, but household fragrances can be a source of hundreds of different chemicals, including VOCs (volatile organic compounds) that can lead to negative health effects ranging from migraines to respiratory issues, immune system problems, cardiovascular issues, and more.
No, we’re not talking about The Force, ESP, or other other-worldly sense that something is amiss. (Although, don’t discount the power of your intuition when it comes to your health!)
When we say “If you feel something, do something,” we’re talking about feeling respiratory, allergic, or other symptoms in your physical body.
Researchers have discovered that kids living in a home that smells musty have double the risk for developing asthma compared to kids living in homes that are mVOC-free.
According to the EPA, the health effects of inhaling mVOCs are largely unknown, although exposure to mVOCs has been linked to:
Everyone breathes in mold spores all day long, which can be found in outdoor and indoor air, mostly without any ill effect. Some people, however, have an allergic reaction similar to asthma symptoms when exposed to high concentrations of mold spores. Other people may develop sinusitis, an inflammation of the sinuses which can lead to infection. In these cases, the immune system is overly sensitive to mold spores and treats them as an invader, triggering a cascade of allergic symptoms.
According to the American Academy of Allergy Asthma & Immunology (AAAAI), symptoms of a mold allergy can look like:
These symptoms are commonly found in an immune reaction to mold, which usually appear as allergy-like or respiratory symptoms.
However, the second type of mold response is an inflammatory reaction to mold.
An inflammatory response to mold is thought to be driven by mycotoxins, naturally occurring toxins produced by mold, which can initiate an inflammatory cytokine-driven response in the body. Although evidence is mounting that the chemicals in the musty odor are a significant variable in the mold and inflammation equation.
According to Parsley Health, this chronic mold-induced inflammation in the body has been linked to a wide variety of ill health effects, including:
As you can guess from looking at this list, the symptoms of mold-related/mycotoxin-induced illnesses could easily be mistaken for something else. Many things can cause inflammatory responses in the body, not just mold. So, inspecting and testing for mold problems in your home can help you and your medical professionals determine if mold is the culprit behind these symptoms.
Did you see a spot of mold, smell a musty odor, or experience a physical symptom related to mold sickness? Then it’s time to do something about it.
As we say here at GOT MOLD?:
“If you see something, smell something, or feel something… do something!”
Mold will not go away on its own. And neither will the physical symptoms that go along with mold allergies or mold toxicity. If you see, smell, or feel something, it’s time to take action. Get a confirmation that you have a mold issue through a mold test kit or inspection, so you can make a plan to get the moisture and mold problem under control.
To learn more about the dangers of excess moisture at your house, or for tips on how to get to the bottom of the issue, read The Complete Guide to Humidity and Moisture in the Home.
Do you know how humid your home is?
Humidity isn’t an issue reserved only for people living in hot, tropical environments. Even if you live in a cold or dry climate, you could still have household humidity issues to worry about. Too much (or too little) humidity can lead to problems, from mold growth to health issues for occupants.
Discover what the ideal humidity level should be in your home—and why it matters for the health and safety of your family.
Before we get into the ideal humidity levels for your home, let’s take a moment to understand better what humidity is and what can impact it in indoor and outdoor environments.
Humidity is the measure of the amount of water vapor in the air.
Remember when you were a kid and learned about the different forms of water? It can be liquid, like the water pouring out of your kitchen sink, solid, like the ice cubes in your freezer, or gaseous, like the water vapor found in the air.
If there is a lot of water vapor in the air, the humidity levels are high.
If you’ve ever been to someplace with high humidity, you’ll recognize the feeling: like you’ve stepped into a steamy shower room and can’t get dry, no matter what. You also likely felt hot and sticky; when the humidity is high, the air gets so clogged with water vapor that there isn’t much room for anything else. Even your sweat can’t evaporate off your body to cool you down because there’s no room in the air for any excess moisture to evaporate off you! You might also notice that cool surfaces, like cold water pipes and tile floors, are damp due to condensation.
If there is minimal water vapor in the air, the humidity levels are low.
If you’ve ever been someplace cold and dry, you’ll know how too little humidity feels. Without enough moisture in the air, your skin and mucous membranes dry out and feel chapped, cracked, and uncomfortable. Too little moisture in the air can also impact immune health, which we’ll learn more about in a minute.
When talking about humidity, what we usually reference is relative humidity or RH, or how much moisture is in the air compared to the maximum amount of moisture that can be contained in the air at a certain temperature. This is expressed as a percentage, as in 50% humidity, or 50% RH.
Another measurement of humidity is called absolute humidity. This represents the weight ratio of vaporized water to 1 kg of dry (moisture-free) air. This measurement is expressed as kg/kg, as in 0.008 kg/kg. This is mostly the measure used by nerds like us who study these things.
When we are measuring humidity levels and discussing the ideal humidity levels in a home, relative humidity is more commonly used.
So let’s focus on relative humidity and the percentages that make up a healthy, comfortable home!
Temperature is one of the more prominent factors when it comes to influencing humidity levels.
Imagine a sponge. As the temperatures increase, that sponge gets larger and can absorb more water (or water vapor, to be more precise). But as the temperatures drop, that sponge gets squeezed smaller and tighter, resulting in less room for water.
Temperature isn’t the only factor that impacts humidity levels, either.
Your everyday household activities can release more water vapor into the air, such as:
Plus, spills and water leaks can also release more water vapor into your home.
Even something as simple as opening a window can impact indoor humidity levels by letting in more water vapor from outside.
If your indoor air becomes too humid, it can result in a myriad of issues, including these five symptoms of excess humidity in the home.
So what is the ideal humidity level for optimal comfort, health, and safety?
According to ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), the ideal indoor humidity range is between 40% and 60%.
Dry indoor air (between 0-40%) becomes a physical health hazard. It can impair the respiratory immune system defenses, allowing viruses to infect us more easily. Plus, evaporation of moisture leads to airborne viruses that can float through the air easier and survive longer, which increases our chance of catching viral illnesses.
Overly-moist indoor air (from 60% to 100%) can also feel uncomfortable to our bodies. But the big concern of overly humid air comes as it creates a water-rich environment for unfriendly organisms to grow and thrive. Mold is just one example of an organism that needs moisture to grow and spread. Another is dust mites, which thrive in humid environments. Between 40% and 50% humidity is ideal for controlling dust mites. Above 50% humidity and dust mites can go from bothersome to out of control.
“Relative humidity of 40-60% in buildings will reduce respiratory infections and save lives,” says Dr. Stephanie Taylor, Infection Control Consultant at Harvard Medical School.
Want to learn more about how moisture can impact the health and safety of your home and what tools can best help you measure, monitor, and control your humidity levels? Check out our Complete Guide to Humidity and Moisture in the Home.
Most people don’t think much about excess humidity or moisture in the home. Until they have a serious problem, that is.
Excess moisture in the home can have a real impact on your comfort, health, and safety.
So before you find yourself fighting a moisture-related issue—like mold or structural damage—you may want to better understand how too much water can negatively impact your home sweet home.
In this guide to humidity and moisture in the home, you’ll get the 101 basics that help contribute to a healthy house, including:
Let’s dive in and find out why excess humidity and moisture can cause so many problems for health and home.
Do you suspect you have a problem with excess moisture or water in your house or apartment?
There are only two possible sources of moisture in your home:
That’s it!
While this seems like a simple answer, moisture issues in the home can be a bit more complex. For starters, there are exterior and interior sources of water. There are many ways excess humidity can build up inside your home.
Excess moisture in the house can lead to issues ranging from structural damage to the building to health issues for your family.
If your house isn’t partially underwater due to a flood, do you really need to worry about a little bit of excess moisture?
Unfortunately, you do. Even a small imbalance can lead to big problems.
Moisture plays an essential role in the life cycle of both your building and the living things inside it. Too much water or excess humidity in your home can speed up the process of life and death for both.
Here are just a few ways excess moisture can cause problems in your home:
Mold is a living organism that needs water, food, and a hospitable environment to grow and thrive. Mold won’t spread and grow in a dry environment; if you have a mold issue, you have a moisture issue. Learn more about how to find mold in your home.
Just like mold, the creatures in and around your home are looking for water, food, and a comfy place to live. Dust mites, insects (including termites and cockroaches), spiders, rodents, and an entire ecosystem of critters can spring up in your home when there is plenty of water to nourish them.
Excess moisture can cause wood to rot and metals to rust. Over time, this degradation of the structural elements of your home can lead to safety issues or even a home that is no longer inhabitable.
Your home is built from materials that can break down when exposed to too much moisture, such as wood and paper. Unfortunately, it’s also built from materials that behave much like a sponge, much like your concrete foundation that can wick moisture out of the soil surrounding it. Unlike concrete, modern building materials can also serve as a nutrient source for fungi.
Mold, critters, and decay can all lead to health issues for the inhabitants of a building. From respiratory problems caused by mold sensitivity to dust mite allergies to diseases caused by rodent droppings, your family may be experiencing health issues that can be tied back to a single problem: too much moisture in the home.
Take a deeper dive into these 5 problematic symptoms of excess humidity in the home.
Flooding in your home is an obvious sign of a problem, but did you know that a water leak can often go undetected in your home long before you see signs of water damage?
And humidity issues may be nearly invisible unless you know exactly where to look.
So how do you know if you have a moisture problem in your house? Use your senses and look for one of these three tell-tale signs.
Bonus sign: you’re paying for it! If you have a water leak in or around your house, an increase in your water bill may be the first sign of a problem, even before you can see, smell, or feel the effects.
If you see something, smell something, or feel something…do something!
Learn more about the 3 Signs You Need to Worry About Moisture and Mold in Your Home.
You may think that humidity is only an issue for people living in tropical climates, but that’s not true.
The term “humidity” refers to the amount of water vapor in the air. Weather changes can impact humidity levels outdoors. Everyday tasks such as showering, cooking, and washing clothes and dishes can also change humidity levels inside your home. So does any significant change in temperature.
How much moisture should be in your home?
The ideal humidity level inside your home is 45% all year round. However, hitting that single target consistently is pretty tricky, especially since you can affect your humidity levels simply by taking a shower or boiling some water for pasta.
Instead of worrying about hitting the magic 45% humidity level, aim for an ideal humidity range instead.
The ideal indoor humidity range in your home is between 40% and 60%, according to ASHRAE.
Learn more about how humidity levels are measured and the negative impact of humidity that’s too high (or too low) in your home.
Monitoring your humidity levels is easier than it sounds (and more affordable than you’d think). Utilize the following devices to keep an eye on your home’s moisture levels, so you can take corrective action when it’s needed.
Many of today’s tools for monitoring/ sensing humidity and water in the home are smart, connected devices. Wi-fi and Bluetooth connectivity and mobile apps are pretty standard, so you can get alerted instantly whenever your humidity levels get too high or too low.
Pro Tip: Focus on your home’s “out of sight, out of mind” spots, as this is where most mold problems manifest. Attics, basements, and crawl spaces are often neglected, and these tucked-away places can be the perfect place for moisture to build up, mold to grow, and beasties and bugs to make themselves at home.
Have your humidity monitors alerted you to excess moisture?
You’ll want to move quickly to control moisture in your home.
Time is of the essence.
Don’t wait to take action when you notice you’ve got a water leak, excess humidity, or other moisture issues.
The industry standard for water damage and mold removal states that you need to take action in the first 24-48 hours to prevent your moisture problem from becoming a mold problem. After 72 hours, the affected areas, especially porous and absorptive materials, should be dealt with as if they are moldy, whether it shows visible signs of mold or not.
There are three easy steps to take to reduce humidity in your house.
It may sound obvious, but the first step to reducing moisture in your house is to stop it at its source.
As mentioned above, many of your everyday tasks can contribute to high humidity in the home. Cooking, showering, washing dishes, and washing clothes are just a few of the activities that can increase indoor humidity levels.
Ventilation requires more than simply opening a window to let the steam from your shower outside. In some cases, opening a window may let even more humidity in from the outdoors and exacerbate your humidity issues.
Exhaust fans in kitchens, bathrooms, and laundry rooms pull excess moisture and fumes from the air and vent outdoors for removal. Be sure to utilize exhaust fans in these rooms while cooking, showering, and doing laundry.
Pro tip: In order to properly ventilate moisture out of the home, all exhaust vents must vent outdoors, not send moisture into the attic or wall cavities. If your exhaust vents are just sending moisture to other parts of the house, they’re not helping to remove excess humidity from the home, and you’re likely causing other problems elsewhere.
Dehumidifiers work by removing moisture from the air and collecting it in a tank. They range from portable units to whole-house add-ons for HVAC systems.
Not all dehumidifiers are created equal. Check out the Consumer Reports Dehumidifier Buying Guide to get dehumidifier ratings for some of the most popular brands.
Set your humidifier at the lowest setting for maximum effectiveness and utilize automatic drainage functions. Most dehumidifiers will empty the moisture they’ve collected via a straw to a floor drain.
Also, keep in mind that air conditioning is not just for cooling. It’s also for dehumidifying. A properly sized air conditioner removes excess moisture from the air in the process of bringing down the temperature.
Pro Tip: Use humidity gauges and dehumidifiers in tandem for maximum effectiveness. Set alerts and utilize mobile apps and automatic settings to ensure your home remains at the ideal indoor levels of humidity: between 40% and 60%.
If you have a moisture problem in your home that isn’t being fixed by removing the source, ventilating with exhaust fans, and running a dehumidifier, it might be time to call in the professionals.
A few of the professionals you may call when you have moisture problems at home include:
Water and mold issues typically require specialized knowledge, expertise, and equipment, something a general contractor or handyman may not be able to take care of.
Seek out a professional who has extensive knowledge of best practices for removing moisture and mold from a home.
Pro Tip: Be cautious of professionals who offer both inspection and remediation services. If your leak or mold inspector benefits from removing and fixing the problem, how do you know if you’re getting an honest inspection result? In some states, like Florida and Texas, it’s actually illegal for a professional to offer both mold inspection and mold remediation services. Learn more about why you should be wary of free mold inspection offers.
Coordinating inspections and repairs is a lot easier when you own your own home. Renters often have to go through property management companies and/ or landlords to schedule inspections and repairs. And a renter is often left to take whatever professional that a property manager or landlord decides to hire, even if that professional has little to no experience in mold, moisture, or leaks. Even if the inspector is experienced, when the landlord is paying the bill, the outcomes are often biased.
If you are a renter and you’re having a hard time getting your landlord to agree to moisture or mold remediation from an experienced professional, don’t worry.
You have options.
First, be sure to document all issues that you’ve noticed. Remember: if you see something, smell something, or feel something… do something. Document all correspondence you’ve had with the landlord or property manager about the issue.
If you’re having physical symptoms that you think are related to excess humidity or mold in your rental, be sure to see a medical professional. Include these visits in your documentation. It can be very helpful to have a letter from your physician explaining that you have a health condition that is caused or aggravated by mold exposure. This can sometimes accelerate things, and can be very useful if you end up in landlord-tenant court.
Next, order a mold test kit and test the air inside your home. Be sure to provide the test results to your landlord and continue to document their response. An at- home test kit is an affordable tool to help identify and confirm a possible mold issue.
From here, you may want to schedule your own inspection. Be ready to pay out of pocket for the professional inspection and request a refund from your landlord, and don’t be surprised if they balk. Again, document every step of the process and all communications with your landlord.
Check out our Renters Playbook to learn more about your rights as a renter and tips to motivate your landlord to take action to control moisture and mold in your home.
A moisture problem is much harder and more costly to address once it’s become a mold problem. And moisture morphs into mold quickly, so don’t wait to optimize the humidity in your home!
You must be vigilant.
Get your humidity gauges in place. Set the parameters to alert you when you’re above 60% or below 40%.
Use your exhaust fans in bathrooms, kitchens, and laundry areas.
Dry wet spots immediately, avoid hanging clothes to dry indoors, and keep windows closed if it’s raining or excessively hot and humid outside.
Watch for signs of a moisture problem, and call a professional if you can’t manage excess moisture on your own.
And remember, If you see something, smell something, or feel something…do something!