Humidifiers vs Air Purifiers: What are the Differences, and Which One is Best for You?

If you’re looking to clean up the air inside your home, then it’s likely you’ll be considering one of two options: either a humidifier or an air purifier. But how exactly do these appliances work, and which one will best fit your requirements? While both are quite different machines that fulfill different needs, they can actually even be used in conjunction to improve the quality of air indoors.

In this guide, we look at humidifiers and air purifiers in more detail, and explain what each one does to help you decide which will be most suitable for your requirements.

What is a humidifier?

In simple terms a humidifier is a device that releases steam and /or water vapor into the air to increase moisture levels and the humidity in a room. It isn’t to be confused with its more common sibling, the dehumidifier, which has the opposite effect, drawing moisture out of the air.

Humidifiers come in all shapes and sizes, with the following being the most common types:

• Evaporators – These use a fan to blow air through a moistened absorbent material, thus adding moisture to the air.

• Central humidifiers – Built into the HVAC (heating, ventilation and air conditioning) system, central humidifiers control the humidity of an entire building.

• Impeller humidifiers – These models utilize a rotating disk to create and distribute a cool mist.

• Steam vaporizers – Powered using electricity, steam vaporizers create a warm mist of steam that’s cooled in the unit before being sprayed out.

• Ultrasonic humidifiers – Using ultrasonic vibrations to create a cool mist. There is currently some debate over whether the mineral particles produced as a byproduct can have negative effects on lung health.

READ NEXT: Best Air-Quality Monitors

What is an air purifier?

Air purifiers are designed to filter the air, often removing both particles and gas, including pollutants such as dust, pollen, and smoke. Air purification systems can be fitted into a HVAC system, but we’re concentrating here on portable units.

Dr Chester Wu, sleep expert, double board-certified physician, and medical reviewer at Rise Science explains: “Air purifiers remove pollutants from the air. These pollutants can include dust, pollen, pet dander, and volatile organic compounds (VOCs). These pollutants can irritate your airways and make it difficult to breathe, which can disrupt your sleep.”

Air purifiers work by using fans to draw air through one or more filters, which trap the various contaminants. This cleaner air is then recirculated into the room. As you can imagine, the most important consideration in an air purifier is the filter or filters. HEPA filters are the gold standard, collecting at least 99.5% of particles of three microns or less in size.

Air purifiers vary according to:

• Type and number of filters used
• How much air they draw through the filter (this will be expressed in cubic feet per minute)
• The square footage covered
• How well they trap pollutants (this will be expressed as a percentage efficiency rate)
• The amount of clean air they deliver
• Weight and ease of portability
• What pollutants and contaminants they target
• The strength of the pollutant source

Most portable air purifiers are also one of three types:

• Filtered air purifiers – These capture airborne particles, trapping them in one or more filters.
• UV light air purifiers – These models use UV light to capture bacteria and viruses.
• Electrostatic air purifiers – These create charged particles to trap particles in the filter(s).

There’s some concern that the last two on this list could produce ozone gas and other pollutants that make them harmful to health, so we’d recommend opting for a filtered air purifier as your safest bet.

READ NEXT: Do dehumidifiers help with mold?

What are the benefits of a humidifier?

Moisture levels in your home can vary depending on the season, weather, and your physical location. If levels are too low or too high, they can have an impact on you, particularly overnight, as Dr Wu clarifies: “Research shows the best humidity level for sleeping is in the range of 30% to 50%. When humidity is too high, above 60%, it can promote growth of mold, mildew, dust mites, and other allergens that can disrupt your sleep. High humidity also causes you to feel stuffy and uncomfortable. On the other hand, very dry air below 30% humidity can irritate airways, increase snoring and sleep apnea, and dry out your sinuses, also disrupting your sleep.”

The sweet spot is 30-50%, minimizing all the above issues. “Proper humidity helps keep nasal passages and airways clear, which allows for easier breathing. This oxygenates the body more efficiently during sleep. Stuffy or dry air can cause sleep disturbances as it can make it harder to breathe”, he adds.
Humidifiers help to maintain perfect humidity levels throughout the day and night, helping to prevent irritation and discomfort. This makes sleep more comfortable for those with asthma, allergies, colds, or flu symptoms.

What are the benefits of an air purifier?

“In general”, says Dr Wu, “an air purifier is a better choice for improving sleep quality if you have allergies or respiratory problems.” Air purifiers can help with various issues throughout the day and night. These include:

• Allergies – An air purifier can remove allergens such as dust, pollen and animal dander from the air, so users should notice a reduction in symptoms. This can be particularly important for children, who can be severely impacted by these allergies.

• Asthma, cold, flu, sinus – Using an air purifier will lead to a marked improvement in air quality. And as we’ve already seen, reducing air pollution can be effective in improving the symptoms of asthma, colds, flu, and blocked sinuses. Asthma sufferers have inflamed bronchial tubes, meaning it’s easier for airborne pollutants to irritate the respiratory system. This can increase the severity and frequency of symptoms, so using an air purifier to help alleviate these issues is an excellent idea.

• Skin conditions – Air pollution can cause skin conditions such as eczema. Again, reducing this pollution via an air purifier can lead to an improvement and reduction in skin rashes and eczema.

• Viruses – A few air purifiers can also reduce airborne particles that contain viruses. However, to do this they need to be able to remove very small particles ranging from 0.1 to 1 micron.

READ NEXT: Does an air purifier remove dust?

Can you use a humidifier and an air purifier together?

The short answer is, yes. This is because the two perform different functions, with the humidifier adding moisture to the air while the air purifier removes airborne pollutants.

For those who do wish to use both together, it’s important to position them at opposite ends of the room. Otherwise, the moisture created by the humidifier could limit the effectiveness of the air purifier, clogging its filters, or even promoting the growth of mold and bacteria on the filters.

You’ll also need to perform regular maintenance. Clean and disinfect the humidifier frequently, using distilled water to avoid any buildup of limescale and mineral deposits. Air purifiers will also need attention; their filters should be cleaned and switched out regularly.

Which should you buy (if you can only afford one)?

Overall, an air purifier is a more useful purchase than a humidifier. A humidifier can help ease allergy and asthma symptoms while it’s on, but an air purifier can actually reduce symptoms and therefore help sufferers. Cleaner air is also healthier for everyone, helping to reduce the risk of serious health conditions from household air pollution.