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Choosing a Room Air Purifier

Here are three recommendations for room air purifiers, each in a different price range. All offer particulate and gas reduction, with medical grade HEPA filters. My thanks to David Barnaby of the Allergy Buyers Club for his input. You can call him at 888-236-7231, x5515.


square feet

Cubic feet of air per hour or minute


Made In

Filter replacement cost
IQAir Health Pro Plus
(See Note below)
1,135 square feet
8’ ceiling
300 CFM or
18,000 CF/hour



Three filters replaced at different times; has indicator with color code:
$69 bottom filter – 18 mos (estimated 10 hrs/day on medium speed)
$99 middle gas filter cartridge – 2 years
$199 HEPA filter – 4 years

Austin Air Health Mate -

15 lbs of carbon

938 square feet
8’ ceiling
250 CFM or
1500 CF/hour


Canada $240/5 years; (filter & particle pre-filter) periodically vacuum from outside to clean large particle pre-filter (perforated holes); $40 large particle pre-filter, could change once a year

Austin Jr Health Mate – 6.5 lbs coconut carbon + zeolite

450 square feet
8’ ceiling

125 CFM or
750 CF/hour


Canada $185/5 years; (filter & particle pre-filter); $33 for large particle pre-filter for the Jr model
Carbon filter can be saturated prematurely, then change whole filter
Note: There are three IQAir HealthPro models: the HealthPro Compact ($800), the HealthPro ($850) and the HealthPro Plus ($900). The recommended model is the HealthPro Plus which filters both particulates and gases. Prices are as of August 2020.

According to an EPA paper on room air filters (available upon request), ions can adhere to respiratory tissue, so we are cautious about units with ionization, such as the AirDoctor and Rabbit Air.

Here is the formula for calculating the number of air changes per hour:

ACPH = CFM x 60 divided by volume (L x W x H)

So, the air changes per hour for each of these three units are as follows for a room that is 20’ long, 20’ wide, and 8’ high, with the units running on high speed:

The air exchanges per hour with each of the three units running on medium speed (the IQ Air has 6 speeds, so this is on speed #3) are:

2-4 ACPH is considered a reasonable minimum that an air purifier should deliver.

The Austin Air should be kept out of moldy or damp areas, because mold and bacteria can grow in carbon. Carbon also adsorbs odors, which can be a double-edged sword, so move the purifier out of the way if painting is going on, carpet cleaning, or if you have odiferous products. One apartment dweller reported that her unit adsorbed a neighbor’s Love My Carpet carpet cleaner, and she had to change out the filter.

Air purifiers don’t work around corners. The square footage is for the room in which the purifier is located.

In addition to a room air purifier, confirm that only a whole house vacuum or a HEPA vacuum cleaner with sealed unit is used in your home. Another way to clean the air is to have a quality 4-5” air filter in your heating and air conditioning system, such as an AprilAir, and to run the fan continuously.

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Next up, we’ll address the list of common indoor air pollutants. That is followed by a ventilation discussion, which includes the consideration of outside air pollutants.

Or, go back to the Indoor Air Quality Topic Index.


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