What’s The Difference Between An Air Purifier And Humidifier?

Are you unsure of the differences between an air purifier and a humidifier? Hey – it’s totally ok! A long time ago so was I!

Ultimately, if you’re reading this post it’s because you’re wondering, “What’s the difference between an air purifier and a humidifier?” As it turns out, they both serve different but important roles in improving the air quality where you live.

As I own both and have benefited from both, I’ll share with you my personal experiences as well.

Infographic – Air purifier and humidifier facts

Difference between air purifier and purifier infographic

What do humidifiers do?

Vicks V745A humidifier image

Common humidifiers like this super-popular Vicks V745 warm mist model take water and use heat to turn it into water vapor that raises humidity. Have you ever noticed how running a hot shower steams your mirrors and raises the moisture in the air? Humidifiers work the same way.

Humidifiers are electromechanical devices that increase the humidity (moisture) level in a room. They work by slowly taking water in a tank and turning it into a fine mist or vapor which rises in the air in the air where they’re used.

While it may not sound like much, humidifiers really can make a really big difference not only on your overall comfort but your health as well!

How they work

A range of different types exist, but most fall into a few basic categories:

Warm mist: uses heat from electrical power to generate steam

Cool mist: uses other methods like an ultrasonic device to change water into vapor (not heated)

Electromechanical: some use an electric motor and blades or another device to stir the water and create a mist

How dry air affects you

Image of a woman with a cold

Speaking from personal experience, during the wintertime I had difficulty sleeping at night due to discomfort in my nose and sinuses. It was mainly due to what happens to our bodies when the air moisture level drops. I also had a painful, dry cough which caused even more suffering!

The mucus linings in your body’s respiratory system and nasal cavities can become more dry than normal, resulting in discomfort. You’re also more susceptible to sickness under these conditions, too.

Additionally, dry skin becomes a concern and it’s especially tough on people with sensitive skin or other issues.

When I caught a cold, it was much harder to sleep because of the dry air. I felt terrible! It wasn’t until investing in a humidifier that I got relief and could sleep better. My cold symptoms were also less severe when using it.

Colds and sinus problems

Your nose needs gooey mucus to trap viruses and other icky invaders before they can get you sick, dry nostrils can also make you more vulnerable to colds, sinus infections, and the flu.

Getting sick is already tough – but it’s even worse in dry air! Maintaining a healthy humidity level is essential for healing cold or other sicknesses. You’re more prone to suffer coughing, sneezing, and even feel the effects of dust and allergens more than you normally would.

I don’t know about you, but I sniffle quite a bit when I’m having nose problems. After using my humidifier I’ve enjoyed much less discomfort than I used to.

Allergies and asthma

Another result is that those with asthma may have an attack triggered. When using the heating system in your home, dust, pollen, and other allergens are often distributed in the air. They can irritate your airways.

If you already suffer from allergies you’re also more likely to feel the effects. Dry air promotes the movement of particulates like allergens and dust more so than a comfortable humidity level does.

Humidity levels and comfort

Relative humidity comfort scale image diagram

What humidity level do I need?

For most people, a comfortable humidity level falls in the range of about 30-50%. However, note that it varies by person.

During the wintertime and when using heat the moisture can drop dramatically – well below 20 and even 10%! That’s an extremely dry condition.

In tropical climates humidity levels are very high. If you’ve even run a hot shower for a long time it’s a similar effect.

While traveling abroad I’ve visited countries where due to the high humidity I was sweating almost constantly and it was very uncomfortable. In high humidity conditions, your body can’t cool itself as it can under normal circumstances.

Use a humidity and temperature gauge

ThermPro TP50 humidity and temperature gauge

An inexpensive temperature and humidity gauge can be used to tell how dry the air is. They’re fantastic for when to use a humidifier. I keep one handy all year round. I love it!

There’s no need to get the moisture in your room or home exactly right – just remember it’s a general range. You can check air conditions where you are using a simple temperature and humidity gauge like the one shown here.

What humidity should I set my humidifier to?

A good rule of thumb is to aim for about 40-50% humidity when using a humidifier and you’ll soon learn what works best for you.

If using a gauge you can see what’s going on in your home and use your humidifier as needed. Not only that but you can see patterns in your home as temperatures rise and fall.

Over time I’ve noticed that when I get the moisture back up above 30% I began feeling better and dry air symptoms stop nearly immediately!

During heavy winters and when my heating system is under heavy use, I set mine to high. Under easier conditions, I set it to low.

What does an air purifier do?

GermGuardian AC4900CA in living room

Air purifiers are often used in living rooms or bedrooms. However, they’re ideally used wherever air quality problems and allergies are a concern. Products like this GermGuardian AC4900CA have a tall “tower” shape. They use electric fans to move air through filters to clean the air.

Unlike a humidifier, an air purifier circulates the air and removes contaminants from the air by trapping them in filters. You might not be aware, but there are lots of unwanted elements in the air around you!

Some of the most common are:

  • Pollen and plant by-products
  • Dust mite elements
  • Dust
  • Pet dander
  • Airborne chemicals and odors
  • Outdoor debris brought in
  • Smoke particles
  • Trace elements of household chemicals

…and that’s just to name a few!

Air purifiers are commonly used to improve air quality by circulating the air in a room and removing foreign matter which causes odors, allergies, and health problems. They’re also capable of helping to prevent sickness by trapping some germs and airborne microbes.

How do purifiers work?

How air purifiers reduce dust diagram

Air purifiers work by using electric fans to draw in air, force it through filters, and blow out clean air.

Note that although several types exist, most are filter-based and use replaceable filter sections to trap particles and even odors in the air. Other types exist such as ozone generators and ionizers, but the most common and most effective products rely on filters and air motion.

As they’re left to run and circulate the air in a room it becomes fresher and healthier as time goes by. Because of dust and other issues reappearing continually, they should be used regularly or as needed.

HEPA, pre-filter, and activated carbon sections

Purifiers are typically designed to work with 3 common types of filters:

  1. Pre-filter section
  2. Activated carbon (charcoal) section
  3. High-Efficiency Particulate Air (HEPA) filter

HEPA filters are made of very dense fiber-like material packed tightly and held inside a rigid frame. They’re designed to be very efficient and they can capture incredibly small particulates in the air down to 0.3 microns in size (A micron is 1/1,000,000 of a meter!). They’re excellent for allergy relief and other air quality issues but don’t really affect odors.

The pre-filter is normally attached to an activated carbon filter section. It’s a thin material that traps larger matter like hair and dust.

GermGuardian FLT11CB4 carbon filter diagramThe activated carbon filter is the portion of an air purifier that absorbs vapors and odors.

After some use a purifier’s filter will become used-up with the matter it has trapped. The carbon filter, after being in use for some time, will lose effectiveness as well.

Most purifiers have about a 6 to 8 months filter lifespan for the prefilter section and 6-8 months life span or even 12 months for the HEPA filter. (Note that the life expectancy relies heavily on the use and conditions)

For this reason, some provide a filter replacement feature to remind you when to check it. Although it varies by manufacturer and product, some allow the filters to be replaced separately while others require replacing a single filter assembly instead.

Air purifier benefits

Dirty air purifier filter that has collected dust

My air purifier’s filter after a few short weeks of use. Lots of dust was removed from the air! I was surprised to see how much dust I had lived with for so long. My purifier reduced the amount of cleaning I had to do.

They’re especially helpful to people with allergies and breathing problems. However, they’re also beneficial in many other ways.

For example, they can help with dust and cut the cleaning you’ll need to do in your home. They can also trap odors and chemical vapors as well.

Pet owners can greatly benefit as pets generate dander and hair which triggers allergic reactions. Smokers or people dealing with cigarette smoke and odors know how strong those problems are.

An air purifier is great for dealing with those problems as well.

Additional features

Some purifiers also include a germ-killing feature to reduce microbes and prevent sickness. Others feature timers, air quality sensing, and even a remote control or smartphone connectivity.

Grant Williams

About the author

Grant is a professional engineer by trade and has experience with both maintenance and do-it-yourself home projects. He enjoys sharing his expertise & ideas with others to help them improve their comfort and quality of life. Read more »

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