Dry Skin, Allergies, or Congestion? The Right Air Device Makes All the Difference
The average person spends around 90 percent of their time indoors, according to the Environmental Protection Agency. Add to that the fact that modern buildings are designed to allow for very little airflow from the outside—resulting in dryer indoor air and allowing dust, pollen, mold, and other allergens to build up inside—and it’s easy to see why maintaining good indoor air quality is so important.
Air purifiers and humidifiers can significantly improve the air quality in your home, but which device is best suited for you? Ahead we break down the differences between air purifiers and humidifiers with help from Michael Rubino, a mold and air quality expert and founder of HomeCleanse, a mold remediation and home wellness service.
Air Purifier vs Humidifier
What each device is designed to do
While air purifiers and humidifiers both have the same goal—improving the air quality in your home—they do so in different ways. An air purifier removes a variety of impurities, including pet dander, dust, pollen, mold, smoke, and even odors, improving the air quality for those who suffer from allergies, asthma, and other respiratory issues.
Humidifiers are designed to add moisture in the air through a variety of processes, including evaporation, sound vibrations, and heating to create steam. By adding moisture to the air, humidifiers help to relieve such issues as dry skin, congestion, and sore throats.
Why air purifiers and humidifiers are often confused
Though they do very different things, they are both sold as portable units designed to improve indoor air quality, which is why people commonly confuse the two. It’s important to note that they accomplish very different things. Unlike air purifiers, a humidifier doesn’t remove contaminants in the air and can actually add mold if it isn't properly cleaned.
Related: Your Fridge Water Dispenser Is Grosser Than You Think. Here’s How to Actually Get It Clean
What an Air Purifier Does
How air purifiers clean the air
An air purifier circulates air through the unit with a fan, cycling it through a series of filters to remove contaminants before circulating the air back into the room. Some air purifiers also circulate air past a UV-C light that kills germs. “Air purifiers work to eliminate particles from our indoor spaces so they don’t continue to build up,” Rubino says. “The more specks of pollen, dust, mold spores, mycotoxins, pet dander, etc. that we can remove from our air, the less there will be entering our bodies and triggering these adverse reactions.”
Common pollutants air purifiers remove
Air purifiers do an excellent job of removing contaminants from the air. They can filter out larger particles, including dust, pollen, and mold, as well as microscopic contaminants, like bacteria and viruses. Some are even capable of removing smoke and VOCs (Volatile Organic Compounds) released by air fresheners, furniture, carpet, and various building materials.
HEPA filters, carbon filters, and other technologies
HEPA: HEPA filters can remove contaminants that are as small as 0.3 microns, including dust, pollen, mold spores, bacteria, and smoke. Rubino advises paying close attention to your air purifier’s filtering ability as not all air filters are alike. “Air purifiers should at least meet HEPA standards, removing 99.97 percent of particles as small as 0.3 microns,” he says. “This covers common air quality contaminants like dust, pollen, pet dander, and mold spores.” He recommends selecting an air purifier that’s capable of filtering out particles even smaller than 0.3 microns.
Activated Carbon: Charcoal has a porous structure that allows it to absorb smoke, gases, and odors. “Opting for a purifier with a carbon filter can help increase its filtration ability and get rid of things like VOCs, flame retardants, phthalates, sulfur dioxide, and nitrogen oxide,” Rubino says.
Other technologies: Some air purifiers even have UV-C light that’s capable of killing germs. High end models use ionizers or electro static filters that charge airborne particles, causing them to clump together on a collection plate, hence removing them from the air.
What a Humidifier Does
How humidifiers add moisture to the air
Humidifiers use four methods to add humidity to your air:
Evaporative: Commonly called cool-mist humidifiers, this type of humidifier circulates air past a wick filter that causes the water to evaporate, releasing water into the air without the use of heat. They’re safer than warm-mist humidifiers but are noisier since they use a fan.
Ultrasonic: Another type of cool mist dehumidifier, this type breaks up water into tiny particles that release into the air using a metal disc that vibrates at high frequencies. Like evaporative models, ultrasonic dehumidifiers also use a fan.
Steam: This warm-mist dehumidifier boils water to create steam that releases into the air, also slightly warming the air. They’re quieter than cool-mist humidifiers because they don’t use a fan but use boiling water that creates a burn risk, making them unsuitable for kids' rooms.
Signs your home air is too dry
You can buy a thermometer/hygrometer that will tell you the humidity of the air in your home. There are also several telltale signs to look for. Some are physical. Dry, itchy, skin, chapped lips, a scratchy throat and nosebleeds are all signs of dry air. Longer periods of dry air can even cause wood furniture and flooring to crack. Dry air can also make the house feel colder and cause more static electric shocks from brushing up against furniture or walking across a carpet.
Ideal indoor humidity levels
The ideal indoor humidity levels are generally between 30 percent and 50 percent humidity. If humidity is too low it can lead to the above issues. Too high and the house can be uncomfortable in warmer weather and also be at risk for mold growth, for which you'd want a dehumidifier to pull excess moisture from the air.
Getty Images
Health Benefits Compared
Air purifier has benefits for allergies and asthma
Air purifiers help those who suffer from asthma and allergies by filtering out particles that trigger asthma and allergy symptoms, including pollen, dust, mold spores, and pet dander.
Humidifier has benefits for dry skin, sinuses, and sleep
By adding moisture to the air, humidifiers have several health benefits. Making the air less dry "helps with symptoms because dry air pulls moisture from areas like nasal passages and skin,” says Rubino. Humidifiers can also alleviate congestion that can cause snoring, promoting better rest.
Air Purifier vs Humidifier by Use Case
Allergies and hay fever
An air purifier is the better choice as it’s equipped with HEPA filters that remove pollen, mold spores, pet dander, dust, and other allergens from the air. A humidifier can help with congestion caused by allergies but can also make them worse should the humidity get too high.
Asthma and breathing issues
An air purifier is the better choice as it removes particles that can trigger asthma and respiratory issues via its HEPA filter.
Dry winter air
A humidifier is the clear choice here as it adds moisture to the air that can soothe dry skin, chapped lips, and dry sinuses.
Pets, smoke, and odors
An air purifier is the best solution for this issue. Air purifiers can filter out pet dander with a HEPA filter while removing smoke and other odors via an activated carbon filter.
Babies and children
It depends. An air purifier is the best choice for babies and children that are suffering from allergies. Go with a cool-mist humidifier to alleviate any congestion or coughing issues. It’s also possible to use both. Always make sure to keep humidifiers clean to ensure they don’t distribute mold spores around the room.
Can You Use an Air Purifier and Humidifier Together?
When using both makes sense
You can use both an air purifier and humidifier together. One removes allergens, odors and other contaminants from the room while a humidifier will help to maintain healthy humidity levels during dryer months.
Placement tips to avoid problems
While it’s fine to use both together, place an air purifier and humidifier in opposite rooms from each other. If the humidifier’s mist is sucked directly into the air purifier, it could damage the purifier’s internal parts.
What to know about combo devices
There are also combination humidifiers that add humidity to the air while also purifying it. These combo units draw air into the unit and filter it through a pre-filter, HEPA filter, and activated carbon filter to remove dust, pollen, odors, smoke and other contaminants. It then circulates the air through an ultrasonic or wick filter to add water to the air before blowing it back out into the room.
Related: How to Clean Stainless Steel Appliances for a Shiny, Streak-Free Finish
Cost, Maintenance, and Upkeep
Upfront costs compared
Humidifiers are generally less expensive than air purifiers, which use more complex technology. Expect to pay $40 for a basic humidifier, with high-end units topping out at about $200. While you can find affordable portable air purifiers for around $50, you’ll pay $200 or more for models that have high-performance HEPA filters.
Filter replacements vs water maintenance
Air purifiers are lower maintenance as they only require periodic filter changes. Humidifiers, in comparison, require almost daily cleaning to prevent mold and bacteria from growing inside them. “Humidifiers can be beneficial for those who are suffering from dry air, if they are used properly and kept clean,” Rubino says. “Otherwise, they could allow for mold or bacterial growth, meaning that you’re blowing contaminants into the air.”
Energy use and noise levels
Both air purifiers and humidifiers are very similar in how much energy they use with both having a typical wattage of between 20 and 100 watts. Humidifiers are noticeably quieter than air purifiers because they lack the fan that air purifiers require to circulate air through a room. Humidifiers produce 14 to 20 decibels while an air purifier can produce 25 and 65 decibels.
Related: How Often Should You Change Your HVAC Filter and Which One Is Best for Your Home?
Common Air Purifier and Humidifier Mistakes
Using a humidifier when humidity is already high
Never use a humidifier when the humidity is already at a comfortable level. Raising the humidity to a high level not only makes a room uncomfortable, it can also cause condensation to form on walls and windows, which can then lead to mold growth.
Expecting a humidifier to remove allergens
Humidifiers can only add moisture to the air to raise humidity. They do not remove any particles, such as dust, pollen, pet dander, or mold spores from the air. In fact, humidifiers can even add allergens to the room if not kept clean.
Skipping regular cleaning and maintenance
Never skip cleaning and maintenance for an air purifier or humidifier. If not regularly cleaned, mold will grow inside a humidifier, causing it to release mold spores into the air. Periodically changing filters is crucial to maintaining air purifiers. Change the HEPA filter every 6 to 12 months depending on how many particles are in the air. Carbon filters require changing every 3 to 6 months to continue absorbing smoke and odors.
Related: The Ultimate Home Maintenance Checklist: Essential Tasks You Should Do Each Season
How to Choose the Right One for Your Home
Questions to ask
There are several factors to consider when shopping for an air purifier. Consider what features the unit has. Many have auto-shutoff, timers, and smart controls that make them easier to use. If you’re using the air purifier or humidifier in a bedroom, look at its noise output.
Room size and climate considerations
Consider the size of the space in which you plan to use either the humidifier or air purifier before making a purchase. Both units should have a rating of how many square feet they can cover. “A purifier should circulate and filter the room’s air multiple times per hour, not just 'occasionally' remove particles,” Rubino says. If you're purchasing an air purifier, also consider what you want to remove and make sure the air purifier you choose is rated to remove those contaminants.
When neither device is necessary
If you aren’t dealing with dry air and your air is clean of allergens like dust, pet dander, pollen, and smoke, then there’s no need to add an air purifier or dehumidifier to your room.
Air Purifier vs Humidifier FAQs
Which is better for allergies?
An air purifier is better for allergies as it’s equipped with filters that can remove a variety of allergens, including mold spores, pollen, pet dander, and dust. Humidifiers don’t remove any particles from the air.
Can a humidifier make air quality worse?
Humidifiers can make air quality worse if you fail to keep them clean. Mold can grow inside a humidifier and be released into the room as it circulates air.
Do air purifiers help with dry air?
Air purifiers, unlike humidifiers, do not add any moisture to the air, therefore they don’t help with dry air.
Is an air purifier-humidifier combo worth it?
An air purifier-humidifier combo is worth it if you’re dealing with dry air and allergens simultaneously. They save space and money over buying the two units individually. You can also use the air purifier part of the unit without having to run the humidifier.