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Do You Need a Dehumidifier in Your Basement?

A dehumidifier in the basement can have many benefits for your entire home. You’ll have less chance of mold, fewer allergic issues, and better longevity for your household items. For these reasons and more, you need one of the best dehumidifiers for basements.

While virtually any home can benefit from a portable dehumidifier in the basement, some homes will need them more than others. In general, there are a few important indicators that tell you whether or not a dehumidifier is needed in your residence.

One of the strongest indicators, and likely the most motivating factor to rush out and buy a dehumidifier, is mold. Fortunately, if you know what to look for, as well as where to look, mold is easy to find.

Look around dark corners and behind appliances; if you see any green, black, or grayish growth, you probably have mold in your basement. Mold not only looks disgusting, it releases spores into the air that can create health risks, especially for people with allergies, asthma, or other respiratory issues.

Even if you can’t see the mold, you may smell it. It often has a musty, earthy smell that gives away its presence. Go into the basement and take a deep breath through your nose; if you smell a musty odor, you may need to add a dehumidifier in your basement.

Condensation around basement windows is also a good indicator of high humidity and excess moisture, which will be reduced with a basement dehumidifier. Look around the edges of windows; do you see any condensation or water gathering near the edges?

If there appears to be excessive moisture, you may have a seeping foundation or dripping pipes that are releasing high amounts of moisture into the basement.

If you have excessive moisture in the basement, you may notice water stains, especially if the basement is finished. If you see a water stain, in the carpet, wall board, or ceiling, you need to check for leaking pipes or another source of condensation.

If you do see water spots, you may need to hire a professional to locate the source of moisture, as they can specifically target the exact source. Obviously the leak will need to be repaired, but a dehumidifier can help reduce many of the lingering moisture issues.

Rotting wood can also indicate a problem with moisture in the basement. If you have noticed that wood around walls and framing is starting to rot, it could be caused by excessive moisture. You’ll not only want to run a dehumidifier, but you may also need to replace the wood that has started to rot.

When moisture levels are high in the basement, it leads to mold and mildew, which can trigger allergies and asthma. If you find that your allergic reactions are more common or more severe in the basement, it may be caused by mold spores that are increased because of high humidity.

You may choose to test the relative humidity in your basement. You can purchase thermostats with a built-in humidistat, which is the term for a device that reads humidity. (Think thermostat, but for humidity.) The EPA recommends keeping humidity levels between 30 and 50%. If, however, you read humidity levels above 60%, you should purchase a basement dehumidifier.

Poor ventilation and air flow between floors is also a reason to purchase a basement dehumidifier. In many homes, basic circulation of air is enough to keep humidity levels in the basement low, as moisture is allowed to flow upward and disperse. However, there are homes that have little air flow, trapping the basement moisture. You can mitigate this potential issue with a basement dehumidifier.

The Benefits of a Dehumidifier in the Basement

Reduce Allergy Triggers

There are many allergy triggers directly related to high levels of moisture in your home, but mold is the most obvious. As it grows, it releases spores, which are microscopic reproduction cells that float in the air and can land in a damp, warm, dark spot where they can grow into a new mold colony.

For mold, releasing spores is a numbers game; the more spores they release, the better their chances of creating new colonies. This means that mold is constantly creating and releasing spores, which are breathed in by people but usually not noticed.

However, those with allergies will notice the presence of mold spores. By reducing humidity levels, you reduce the chances of mold, reducing the chances of spores, and thereby reducing the chances of allergic reactions.

Other allergens that are increased by excessive moisture include leavings from pests and insects, as well as dust mites. With a dehumidifier, you don’t eliminate allergic reactions, but you do reduce the severity and frequency of the problem.


Reduce Asthma Attacks

Research has shown that people who are exposed to mold as a child have a higher chance of developing asthma that can last into adulthood.

This asthma often leads to respiratory and breathing issues that last for years and make certain activities more difficult. A dehumidifier could potentially lead to fewer asthma developments as well as fewer asthma attacks among people already afflicted with the condition.


Protect Your Home From Damage

Moisture can wreak havoc on your home, including your woodwork, sheetrock, cabinetry, and more. Warping, for example, is an issue caused by prolonged high humidity. Excess moisture causes wood to warp and bend, a problem that can impact your floors, door frames, trim work, crown molding, and exposed framing.

Rust can also occur if you have high levels of excess moisture. Rust occurs in many metals and is increased with the presence of water. If you have any metal trim work or decorative fixtures that are susceptible to rust, they could be in danger if you have higher levels of relative humidity.


Protect Items in the Home

There are many household items that can be vulnerable to high moisture, and many of your favorite keepsakes can be in danger if you don’t use a dehumidifier.

For example, if you have a collection of vinyl records, high relative humidity will warp their shape, making them unplayable and far less valuable (if not worthless) as a collector’s item. Damage to records is increased if heat is added to the humidity.

If you store clothing in the basement, high humidity increases the chances of mold growth on your favorite garments. Excess moisture leads to mold and mildew, which loves to find a comfortable home on your clothes. If you have a damp basement where any garments are stored, a dehumidifier can help maintain their quality and consistency.

Electronics are also vulnerable to moisture. Relative humidity can create issues by breaking down and corroding some of the metal in your electronics, and even if you don’t have electronics in the basement, humidity can float upwards and impact the electronics you have on the main floor.


Improve Odors in the Home

Because mold leaves a musty smell, reducing smell can be one of the biggest advantages to using a dehumidifier. Your home may have a moldy, musty smell that makes you avoid the basement, but this issue can be reduced if you use a basement dehumidifier.


What Should You Look for in a Basement Dehumidifier?

Water Removal and Storage

An important factor for selecting a basement dehumidifier is how the machine stores or removes water. Most household dehumidifiers have a collection reservoir that stores the water. When the machine pulls moisture from the air, it is funneled to a reservoir that slowly fills. Eventually this reservoir will need to be emptied, and it will also need to be cleaned frequently.

You should know that when the tank is full the dehumidifier will stop operating. So, it's important to check it regularly so it can continue to operate.

The other way that dehumidifiers remove water is with a hose. Some appliances are equipped with hoses or a hose connection that allows you to move the water straight to a floor drain; no need to empty a reservoir, and no chance that the reservoir will overflow if it’s not emptied. A basement dehumidifier that empties through the floor drain is often preferred.



Dehumidifiers are largely measured by an important statistic: pints removed per day. So if you are shopping for a dehumidifier and see 30 pints or 30-pint dehumidifier, it simply means that that unit is capable of pulling 30 pints of moisture per day. The capacity is essentially connected to the amount of space it can effectively dehumidify. So if you know the square footage of the basement, you can more or less estimate the capacity you need for a dehumidifier.

However, you will also need to consider the level of humidity in the air; the higher the humidity, the more capacity you will need from your dehumidifier.

So if you have a small space with relatively low humidity, you likely won’t need a high-capacity dehumidifier. However, if you have the same humidity in a large space, a bigger capacity may be needed. Likewise, if you have a small space with high humidity, a large capacity could be required.

According to Sylvane, one of the top distributors of dehumidifiers and other household appliances, if you have a 300-square-foot space with only slightly-damp conditions, which they categorize as 50 to 60% humidity, a 30-pint capacity will do. However, if the space is slightly damp but measures 1,500 square feet, you will need a capacity of 70 pints.

If the area is wet, which means 85 to 100% humidity, then you’ll need higher capacity. For a 300-square-foot space with wet conditions, you’ll need a capacity of at least 40 pints. If the space is 1,500 square feet, then you need at least 90 pints per day.

Sylvane adds a few additional factors to be considered. If you live in a high-humid area, they recommend adding 10 pints-per-day to the requirements. If people spend time in the space, such as a finished basement, if there are multiple windows and doors, or if there are laundry appliances, then add another 5 to the total.


Are Basement Dehumidifiers Better During Certain Seasons?

While a portable basement dehumidifier can be useful in any season, assuming conditions are damp and humid, there are times of the year when they are more preferable than others. Most of all, if the humidity is high, then you will want a dehumidifier; however, even if outside conditions are dry, you may benefit from using a dehumidifier in the basement.

Let’s take a closer look at how you might use a dehumidifier in each season:



For most homes, the winter months are when you need a dehumidifier the least. However, there are situations when a dehumidifier can be useful from November to March. Winter generally sees the driest conditions as far as airborne humidity, but it may still be useful to have a dehumidifier running if you have a particularly damp basement. However, in dry conditions, running the dehumidifier can damage the machine, so you may want to test the air and shut off the machine if needed.



Spring may not have the high humidity of most summer months, but it can still be a time when dehumidifiers are needed. Most people have stored away their dehumidifiers for the winter, so most of all this is a time to unpack, dust off, and position the dehumidifier so it’s ready when the humidity rises. If you live in a region that gets lots of rain during spring, then you’ll want to keep it ready, especially if that rain results in seepage in your basement. It’s not just a sudden rain shower you want to watch for, but the cumulative effect of frequent rains. If it’s been a wet spring, with seemingly endless showers, then you’ll likely need to keep the dehumidifier running.



Summer is likely the #1 season for portable dehumidifier use. During the summer, in regions all through the country but especially the Midwest and Southeast, humidity levels can be extremely high. This high humidity not only makes the outside world uncomfortable, it can also impact the quality of your indoor air. For this reason, some people use their dehumidifier almost nonstop throughout the summer. During the summer, when humidity is high, you’ll also need to check your dehumidifier water reservoir more often. The machine will be collecting more water, which means you will need to empty the container more than usual.



Autumn is a tricky season to predict when it comes to dehumidifier use. Some years, fall seems like a mere extension of summer, with hot weather and high humidity that lasts into October. Other years, it seems like winter comes around before October starts. Like the spring, you’ll want to monitor the weather, including humidity levels, to see if a dehumidifier is appropriate during the fall.


Maintaining a Basement Dehumidifier: What is Required?

Like all machines, dehumidifiers need to be properly maintained to ensure consistent performance for years to come. Many dehumidifiers have filters that need to be replaced on a regular basis. The filter protects the internal components of the dehumidifier and helps ensure consistent and efficient operation. You’ll want to check the manufacturer’s recommended timeframe for filter replacements, as each machine will be different.

You also have to clean the water container frequently. Simply emptying the tank won’t guarantee a perfectly-clean receptacle, as it also needs to be cleaned and sanitized to reduce the chances of mold growth.

Learn where the condenser coil is located and check it for frost and ice. When operating at cool temperatures, the condenser coil can be covered with ice and frost, which will disrupt proper operation. If you see ice on the coil, unplug the machine then check your owner’s manual for instructions on properly cleaning the coils. You may have to warm the space that is being treated, as cooler temperatures could be causing the issue.

A dehumidifier also has air intake and exhaust grilles, which need to be cleaned regularly. Dirty grilles will lead to poor performance. For most homes, these simply need to be cleaned about once a year, but if you run your dehumidifier more often, you may need to clean it twice a year.

You should also avoid turning the dehumidifier on and off rapidly. If you turn the machine off, wait ten minutes before starting it again. This time allows the pressure in the system to equalize and prevent damage to the compressor, but turning it on and off frequently can cause an overheating issue. It also leads to inefficient moisture removal. You may choose to purchase a dehumidifier that has an automatic delay, which protects the compressor from damage.


Improve Your Indoor Air Quality with Oransi

Basement dehumidifiers are an important machine for maintaining excellent air quality all throughout the year. Another important appliance for air quality is an air purifier. By removing allergens and airborne pollution, purifiers ensure cleaner, healthier air for you and your family.

Browse our complete selection of air purifiers to find the right unit for your home!