Best Air Purifiers & HEPA Air Filters

Air Purifiers for Allergies, Air Purifiers for Dust & Air Purifiers for Mold

Understanding Air Purifier Technology

The best performing air purifiers feature more than one filter technology, and using HEPA style filtration is the key to optimal results. Filtration performance is not ideal without the use of HEPA air purifiers, and symptoms of particle pollution, like allergies and asthma, are not reduced.

HEPA Air Purifiers

Developed in the 1940s, High Efficiency Particulate Air (HEPA) technology was made popular by use in medical cleanrooms, and it is still the most reliable and effective technology used. Air purifiers equipped with a HEPA air filter absorb up to 99.97% of all particles, like allergens, pollen, dust, dander, and others that are 0.03 microns and larger in size; harmful indoor air particles that cause allergy and asthma symptoms are measured to be about 0.03 microns or larger. Air purifiers like Alen and Blueair use HEPA in combination with electrostaticity, which allows an electrical charge to trap particles traveling in the air stream. As a result, more particles are gathered and the charged particles are brought directly to the HEPA air filter which captures them. Bacteria, dust, and pollen and other microscopic particles are absorbed by HEPA air filters, so the air that re-circulates in your home is clean, fresh, and scarce of harmful contaminants.

Electrostatic Air Purifiers

An electrostatic air purifier is very similar to HEPA air purifiers, except they do not use air filters. Electrostatic air purifiers use an electrical charge to trap particles traveling in the air stream. As a result, the charged particles stick to the sides of the internal filtration system on collection plates, but only about 30% of particles are removed from your indoor air. Electronic air purifiers are low maintenance and only require cleaning of the collection plates for optimal efficiency. However, like with the Ionic Breeze air purifier from Sharper Image, electronic air purifiers were found not to take in all the air in an enclosed room. It was measured to have left about 5% of the contaminated air in the room to circulate without it ever being absorbed by the purifier. Consumer Reports gave the Ionic Breeze air purifier a “poor” rating. Although they are readily available, consumers who research air purifier technologies before making a purchase are sure to avoid Ionic Breeze and electrostatic models.

Ozone Generators

Ozone generators are air purifiers that intentionally produce ozone. Not all are effective, but some are not even appropriate for home use, like ozone generators. Ozone generators are not effective air purifiers for your home; they can be harmful to your family and can cause health problems, including respiratory tract irritation and breathing difficulty. Historically, ozone generators have been used in commercial applications to purify the air and remove airborne particles, chemicals, mold, viruses, bacteria, and odors. However, ozone is not effective at cleaning the air except at extremely high, unsafe ozone levels.

Technologies That Complement HEPA Style Filtration

The best technology to pair with HEPA style filtration in air purifiers really depends on your concern. There are many different technologies that are used in air purifiers with HEPA style filtration, such as activated carbon, pre-filters, ultraviolet light, and ionizers. Choosing the best air purifier with the most efficient technology can be easy with some research and comparison. While searching through many air purifiers to find your perfect solution, be aware that the technology used is the most important factor you should consider.


A pre-filter captures the largest particles before they reach the more expensive HEPA filter. Most of the particles in your air are large particles like dander and dust, not tiny ones like pollens and microbes. Even though HEPA filters have a large number of pleats to maximize their surface area, they can fill up quickly if larger particles are not pre-filtered out.

Activated Carbon

Elements like activated carbon, zeolite, or potassium permanganate are added to air purifier filters to increase efficiency to the filtering system. These elements work to absorb smoke, gases, chemicals, and odors that are present in the air. Activated carbon neutralizes odors and traps harmful chemicals and gases in its pores to provide relief from activities like secondhand smoke, off-gassing from plastics, and harmful fumes produced from renovations. An effective filtering system that is also equipped with chemical adsorption materials can produce cleaner and fresher-smelling air.

Ultraviolet Light

Ultraviolet light (UV) technology is key to neutralizing viruses and bacteria that accumulate on air purifier air filters. It is important to use the UV technology in combination with HEPA air filters and possibly activated carbon. Without a particulate filter system like a HEPA air filter, too many microorganisms may be hidden from the UV light, since it is not easily located on an air filter.