HEPA Air Purifiers Buyers Guide

HEPA air purifiers buyers guide gives insight into HEPA air purifiers, that are reviewed elsewhere on this site. Also, use HEPA air purifiers frequently asked questions to help you find the best.

Auto Mode

First of all, the primary function of the air purifier is to clean the air in a room. For the purification to occur, air in the room has to go through filters that capture pollutants in the air. Meanwhile, fans force the air through purifiers. Now, there are two ways these fans can work. The first is by manually turning the fans on or off. While the alternate way is for the air purifier to monitor pollutant level in the air and automatically turn the fans on or off depending on the pollutant level. In fact, this auto mode is a far more convenient and energy efficient way to operate the air purifier.


Now, filters help remove pollutants from the air. So, the more the better. But, not always. For example, if you don't have pets in the home, there is no need to have a filter that helps remove pet dander, hair, and odor.

First, a pre filter traps dust, pet hair, and other large particles.

Second, a HEPA filter that removes 99.97 percent of particles as small as 0.3 microns or even smaller.

Third, a carbon filter, made from activated carbon granules helps reduce Volatile Organic Compounds or VOCs, and household odors from cooking, pets, and smoke.

Fourth, an Ionizer, which releases negatively charged ions (known as anions) that can, for example, neutralize or eliminate odors, smoke.

Fifth, an anion generator that produces negative ions to charge particles and trap them inside the unit for that feeling of freshness.

Lastly, an anti-bacterial filter to capture bacteria and germs.

Size of Room

Now, the size of the room matters. In fact, each HEPA air purifier specifies the optimum square footage of the room the air purifier is designed for. For example, a small room is usually around 200 to 300 square feet. Meanwhile, master bedrooms or living rooms can be anywhere from 400 to 800 square feet. So, one of the first things to do is measure the square footage of the room where you want purified air.

Size of Air Purifier

Meanwhile, air purifiers come in various sizes to accommodate different room sizes. For instance, the following gives some insight.

First, small air purifiers are designed for personal space or rooms up to 300 square feet.

Second, medium air purifiers are designed for rooms between 300 to 700 square feet.

Third, large air purifiers are designed for room between 700 t0 2,000 square feet.

Lastly, whole house air purifiers are designed for purifying air in the whole house.


Next, an air purifier should never be louder than an ordinary pedestal house fan.


Finally, even though air purifiers will be running 24 hours a day, 7 days a week, they should still last for at least four or five years. Therefore, they should have a warranty that covers at least one or two years.