Do Dehumidifiers Improve Air Quality?


Air quality refers to the condition of air in the surrounding. Good air quality means the air is free from air pollutants, and the level of health, safety, and comfort inside the home is high.

Mold, gasses, and dust can negatively impact air quality, and its prolonged exposure could result in respiratory and nervous system diseases. 

A dehumidifier’s purpose is to reduces humidity in indoor air, but do dehumidifiers improve air quality? Yes, Dehumidifiers improve air quality by reducing the ability of bacteria, mold, and dust mites to grow in the home. Those organic pollutants thrive in relative humidity (RH) levels above 70%, so lowering humidity will inevitably stop their growth and as a byproduct, improve air quality.

Indoor air quality might not be something you think about daily, but poor air quality can have both long and short-term impacts on your health. Therefore, the problems related to poor air quality and the methods to make indoor air clean should be discussed.


Signs of Poor Air Quality

Clean air is vital to good health, especially indoor air, as we spend as much as 75% of our time indoors, yet indoor air is more polluted than outdoor air.

As the air is not visible; therefore, not much attention is given to its pollution, but certain symptoms warn about the poor indoor air quality.


  • Common Cold

There are many symptoms of poor indoor air quality that can be mistaken for the common cold. If you are suffering from flu, runny nose, eye irritation, coughing, sneezing, nausea, or dizziness for more than one week, it might be a common cold.

But, if you feel these symptoms when you are at home and get better when you leave home, it might be due to the poor indoor air quality; these symptoms of common cold occur due to a single or multiple exposures to certain airborne pollutants.


  • Excessive Dust

Excessive dust particles inside the house also indicate the poor air quality of the house. These dust particles move freely in the home and can be noticed on the furniture, ceiling fans, and your home’s air filters.

The polluted air has dust mites and contains mold, pet dander, and other allergy triggers. People who have asthma and other allergies will show symptoms more immediately than others.


  • Hot and Cold Spots

If you are experiencing hot and cold spots in your home, it means that the air inside your home is not properly circulating. This inconsistency in air distribution can be due to the improper maintenance of your house’s HVAC system.

If the air is not properly distributed, home ventilation is also not adequate, which can become a reason for mold and mildew to grow.


  • Unpleasant Odors

Poor air quality inside the house also leads to unpleasant smells. If the house is tightly sealed and there is no proper ventilation mode, it’s more likely to have unpleasant smells inside which cannot leave.

This unpleasant odor can be due to mold growth, pest infestation, and other chemicals released from the furniture. These odors are not noticeable when you are inside for long but coming back home after a while may help you notice them.


Causes of Poor Air Quality

The products which we use daily at our home also produce pollutants. These pollutants release gases and dust particles into the air, which are the main reason for poor indoor air quality.

Although a dehumidifier won’t be able to help you remove these pollutants, it’s important to be able to look at the whole picture.

There’s no point in using a dehumidifier to just reduce humidity so that you can eliminate mold and dust mites. There are still other pollutants inside the home that need to be addressed with fresh ventilation, air purifiers, specialized filters (like HEPA or activated carbon) and regular maintenance of combustible appliances and your HVAC system.

So let’s take a look at some potential problems you may wish to also put on your to-do list.


  •         Inadequate Ventilation

The main source of poor air quality is improper ventilation, making the air stale as the fresh air does not come inside from outside. This stale air is usually caused by cooking smells, the smoke of cigarettes, and bathroom odors.

Moreover, poor ventilation eventually results in building up carbon dioxide, which can become a reason for headaches and fatigue. And even worse, a lack of fresh oxygen inside the home can even cause carbon monoxide to build up. You can read more about carbon monoxide and its dangers in this post.


  •         Carpet Fumes

The adhesives used in the carpet installation are bad to breathe in as they release chemicals long after the installation. This chemical releasing process is known as off-gassing, and it might cause dizziness, nausea, and shortness of breath.

Moreover, carpets are considered a health hazard as they can be home to a thousand dust mites. The norovirus which causes stomach flu can survive on unclean carpets. Therefore, the carpeting may not be the best choice for people having allergy issues.

Some other flooring like laminate have also come under scrutiny for pollutants like formaldehyde. Although manufacturers are getting better at reducing levels inside those synthetic flooring products, it’s still important to pay attention to them. Especially if you have small children.


  •         Combustion Products

Indoor combustion pollutants can come from both indoor and outdoor sources. Indoor sources can include gas heaters, ovens, scented candles, wood or coal-burning stoves, fireplaces, etc.

Outdoor pollutant sources can be automobile and lawn mower exhaust, internal combustion engines, wood burning, soldering, etc. Combustion products that are vented or non-vented generate carbon monoxide, nitric oxide, sulfur dioxide, among others, which can cause fatigue, dizziness, and nausea.


  •         Volatile Organic Compounds (VOCs)

Volatile organic compounds (VOCs) are released in the form of gasses from certain solids and liquids. They include chemicals that can have both long and short-term impacts on health. VOCs are found indoors more than outdoors, as many products inside our homes are simply part of the home’s construction, furniture, or everyday household products.

Paints, waxing, varnishing, and cosmetic, cleaning, and disinfecting products contain organic solvents and release organic compounds when you use them. Excessive use of such products can cause allergic skin reactions, liver and kidney damage, eye irritation, among others.

Although we often hear horror stories about old homes with asbestos and lead pipes, in reality, it’s actually the newly manufactured homes that are causing problems more commonly nowadays. Their airtight construction makes ventilation even more difficult and it can take years for VOCs to off-gas.


How Does a Dehumidifier Improve Air Quality?

A dehumidifier is equipment used to decrease the humidity level inside the house. The ideal humidity level inside the house should range between 35 to 50 percent.

An environment with a humidity level of more than 50 percent (and especially 70 percent) becomes a medium for various allergens such as mold, mildew, and dust mites to grow. A dehumidifier reduces the humidity by taking the moist air in from one side of the grill and releasing the moisture-free and less dense air outside from the other side.


  • Reduces Mold and Mildew Growth

Dehumidifiers create an unfavorable environment for mold to grow. Like all living things, mold needs moisture to grow and reproduce its spores, but using a dehumidifier reduces the moisture from the air and controls mold growth.

It should be kept in mind that the dehumidifiers don’t kill the mold but only reduce the medium through which they grow. To eliminate the mold, you will have to immediately seek help from mold mediation experts if the case is serious. For milder cases, persistently wiping down walls and surfaces with bleach, regular cleaning, and regularly capturing and filtering mold through a potent air purifier can work. Although, it can take time to see results as mold is very persistent.

It’s important to understand that a dehumidifier won’t directly kill mold, but it can stop or reduce its growth. This post goes into more detail about that very topic.


  • Eliminates Allergies

A dehumidifier makes the air less humid and helps control the allergies triggered by dust mites and different types of viruses.

The most common symptoms of having allergies are a stuffy nose, skin and eye irritation, and bad throat.


  • Helps Your HVAC System

During the hot and humid weather, the HVAC system has to work more than usual to make the air cool and clean. The air becomes less dense by using the dehumidifier, and it becomes easy for the HVAC system to work more efficiently.

Using a dehumidifier will also eliminate the HVAC system’s repairing cost. You might have to pay the repairing cost due to the HVAC system’s overwork in the absence of a dehumidifier.


Related Questions

Can I sleep in a room with a dehumidifier?

To maintain the ideal environment, leaving the dehumidifier on overnight is necessary, but people don’t usually leave it due to overheating and fire hazard if left unattended.

Most people leave the dehumidifier on at night as they think that it makes them sleep better. But this does not always work, as the dehumidifier works according to the humidity level and the weather conditions.


Why is air quality an issue?

Indoor air quality is a major issue as most of the time is spent inside the house. In extreme weather, the house windows stay closed, and the house’s air pollutants have no way out.

These air pollutants can have severe long- and short-term impacts on our health. Such air can be very dangerous for children and older people as this air can become a cause of asthma and many other respiratory diseases.


What should one do to improve indoor air quality?

There are many ways through which you can improve the air quality of your house. Make sure to change your air filters from time to time and maintain your HVAC system. 

Use dehumidifiers to reduce the level of humidity inside your house. Vacuum daily to reduce the dust particles inside the house so that the dust allergies can be controlled.


Where should I place my dehumidifier?

Dehumidifiers are best placed directly in the space where a moisture problem exists, at least a foot or two away from the walls. For example, if you have a damp bathroom, place the dehumidifier directly on the bathroom floor and not the hallway inside. If there is no space, you’ll have to get creative. Maybe a small dehumidifier can be installed on a shelf, near an electrical outlet so you can plug it in.


Will a dehumidifier in the basement help the whole house?

More than likely, it will not.

Even large capacity portable dehumidifiers (70 or 90 pints) are limited to a single floor. And considering just how damp basements are and how much moisture tends to seep through their foundation floors and walls anyway, it’s unrealistic to expect that.

However, there are whole house dehumidifier systems that can be installed instead of just having to scatter clunky portable dehumidifiers all over your house. They attach to your HVAC system and will cost about $1,500 to $3,000.