Overview:  We tested models from 6 manufacturers at our offices with a high-tech particle counter to measured the ability to remove particles from the air which are 0.3 microns and larger.  This represents all pollen, mold spores, pet dander and most of the dust in a home.

Recommendations: We recommend that customers consider purchasing either the IQAir HealthPro, Alen A350 or the BlueAir 601 units as these units remove over 95% of air borne particles.  The Austin Air HealthMate is above average performer but may not be suitable for people with severe allergies.   We are not recommending the Friedrich C-90A unit even though the unit did well in particle removal.  The main reason is the unit generates ozone and produces a musty smell.  Based on several studies conducted by California DHS' Indoor Air Quality Program, ozone is harmful to the body.  Lastly the Oreck air purifier did the worst of all of the units with a 45% particle removal rate - which means the unit allows more than 1/2 of all particles to go right through the machine!  We recommend avoiding this unit completely.  A detailed review of each of these units are listed below.

Test Result Rankings:

1.      IQAir HealthPro ($699):  The IQAir model was the top performer and removed 100% of the particles when measured at the air output and removed 98% of the particles in the room after running for 20 minutes.   The IQAir uses only HEPA filters and performed equally well at each fan speed.

2.      Alen A350 ($349):  The Alen A350 air purifier removed 98% of the particles at the unit and 97% of the particles in the room.  This unit performs as well as the more expensive units like IQAir and BlueAir in dust and pollen removal, but cost half as much.  The other advantage to this unit is the low filter replacement costs which is economical to own and operate.

3.      BlueAir 601 ($599):  The BlueAir 601 removed 98% of the particles measured at the unit and 96% of the particles in the room.  This model uses a combination of ionization and HEPA-like filters.  The filters are about half as dense as the IQAir filters however the ionization effect seems to compensate. The particle removal rate was lower at the higher fan speeds and this is likely due to the filters not being able to "catch" as many particles.

4.      ($399):   The Austin Air Healthmate removed 84% of the particles when measured at the unit and 80% of the particles in the room.  The HealthMate uses a cylinder shaped HEPA filter and also contains carbon for odor removal, although we did not test for odor removal in our study.

5.      ($499):  The Friedrich C-90A removed 68% of the particles when measured at the unit and 90% in the room.  The C-90A uses electrostatic plates to charge and catch the particles as they pass through.  At the higher fan speeds the performance was worse and we attribute this to the air moving too quickly for the particles to attach to the plates.  The performance in the room was better than at the unit and we speculate that the particles weren't actually removed but were charged and stuck to the walls and carpeting in the room.

6.      Oreck Air Purifier ($349):  The Oreck air purifier was one of the worst performing unit of those that we tested, in that it removed 33% of the particles at the unit and 45% in the room.  This is similar to the Friedrich C-90A in technology, only smaller and more attractive.  It had the same issue as the C-90A on the higher speeds in that fewer particles were being trapped in the unit.  Also, it appears to emit a small amount of ozone and one of our employees complained about an odor and had a headache when the unit was run.

7.      Sharper Imaage Quadra Ionic Breeze Air Purifier ($350):  The Sharper Image air purifier was the worst performing unit we tested, in that it only removed 30% of the particles at the unit and 5% in the room - we were generous with the 5%.  We even tested this unit beyond our standard 20 minute duration and extended it for an entire day.  This unit still didn't remove any significant particles from the room.  We did not see a layer of dust on the electrostatic plates during our test.

How the Testing was Conducted:

To establish the baseline for the number of particles removed from the air, we first ran the particle counter for 5 minutes and took an average of the readings of particles that are 0.3 microns and larger.  Each model was then run on high speed and the particle counter placed at the air output of the air purifier to measure the performance in removing the particles at the air purifier.

For the particle removal of the room, we tested each unit in one of our 132 sq foot rooms in our office with each model located in the same place in the room.  Each model was run for 20 minutes on high speed with the particle counter placed in the center of the room with the door and windows closed.  The particle count was taken after the 20 minutes had completed.  The air ventilation system was shut off during the testing so as not to influence the results.  Before each unit was tested, we allowed the particle count in the room to return to the baseline particle level so each unit would start from the same place with respect to the number of particles in the air.