Humidifiers vs Dehumidifiers vs Purifiers: Which Do I Really Need?

AT THEIR MOST BASIC, dehumidifiers, humidifiers and air purifiers may seem like relatively similar devices. All are square, and sometimes expensive, devices that help correct air quality problems using some form of filter. Yet each performs an extremely different function. Here’s a guide to their most important features and tips on how best to use them.



Valero Doval

A large glass of water

In winter, if you spend most of your time cooped up next to heaters, your skin can become incredibly dry. It’s also common to have dry eyes, chapped lips, or worse, regular nosebleeds. A humidifier adds moisture to the air in your home and may help sufferers, according to Dr. Dawn Davis, a dermatologist at the Mayo Clinic in Rochester, Minnesota. While all humidifiers draw from a reservoir of water, they work in one of two ways. Ultrasonic humidifiers use rapid vibrations to propel a mist of water through your air. Evaporative humidifiers, on the other hand, heat water until it becomes steam, then use a fan to push it through a filter. Both types work, although ultrasound, like this Levoit Classic 300s, tend to run quieter and can be dismantled more easily for cleaning. Be sure to wipe down all parts of the humidifier daily and disinfect the tank with a vinegar solution at least every two weeks so that no microorganisms can grow in standing water.



Valero Doval

For swampy days

While high humidity environments are great for some tropical plants and our skin, organisms like dust mites and mold also find them hospitable. This can make humid environments unpleasant for people with allergies or asthma, said Jose Jimenez, professor of chemistry at the University of Colorado at Boulder. Mold growth can also damage your furniture, wallpaper, and floors. With dehumidifiers, you again have two choices: Desiccant dehumidifiers absorb water using a material such as the silica gel packs that come with new shoes. Refrigerants, such as Frigidaire FFAD2233W1, use a fan to draw moist air through a filter and pass it over a cold metal plate. Once the water present in the air has condensed on this plate, it is routed to the water tank of the device. The handle on the 22-quart tank on this Frigidaire model makes it easy to dispose of that excess water, a big plus since you’ll be emptying the tank at least every day you use it. Clean it (and the filter) every time you use it.



Valero Doval

Out, cursed particle!

Air purifiers– the trade name for what some call “air purifiers” – are designed to remove pollutants, which can trigger respiratory problems. These irritants can result from household activities, such as cooking with gas or lighting candles. Environmental factors, such as Covid-19 or smoke from wildfires, can also contribute. The best purifiers use high-efficiency particulate filters (HEPA), made from pleated fiberglass. These trap most particles larger than 0.3 microns. (Pollen, for context, is usually no smaller than 10 microns.) Commercial air purifiers, like this one Coway Airmega AP-1512HH, use HEPA filters in conjunction with powerful fans that quickly draw in air and direct it through the filter. You could, Professor Jimenez notes, get close to that by sticking a HEPA filter from a hardware store to a box fan. But the Coway purifier is a lot more attractive, probably a lot quieter, and can scale its efforts to the amount of irritants it detects in your air.

The Wall Street Journal is not compensated by retailers listed in its articles as outlets for products. Listed retailers are often not the only retail outlets.


How do you use humidifiers, dehumidifiers and/or purifiers in your home? Join the conversation below.

Copyright ©2022 Dow Jones & Company, Inc. All rights reserved. 87990cbe856818d5eddac44c7b1cdeb8

Appeared in the August 6, 2022 print edition as “There was something in the air that night…Now help me get it out”.