Air purifiers with filters are the most common. During operation, these models pull air inside the machine and pass it through a series of fabric filters and/or absorbent carbon filters using the power of a circulating fan.

As air moves through each filter, airborne particles and pollutants are filtered out and locked away in the filter. Clean air is then circulated back into your space.

This process continues for as long as you keep the air purifier turned on. Filter air purifiers are popular choices if you’re looking for HEPA-level filtration (High Efficiency Particulate Air filtration) in your indoor environment—a must if you have allergies. Read more about HEPA filters in our All About Air Purifier Filters article.

These air purifiersuse ultraviolet (UV) germicidal light to kill allergens and germs on contact as air passes through the unit. With these models, UV light is usually used alongside another type of filtration like filters for the most effectiveness.

UV air purifiers are considered completely safe because ultraviolet light is only used inside the unit and will not escape to harm your skin or eyes. However, recent research has shown that these units may not be as effective as some manufacturers claim. UV light needs a certain timeframe – a few minutes at least – to kill allergens and germs.

Because air so rapidly passes through a UV air purifier, the light shines only for a few seconds with each pass. This is usually not enough to neutralize all allergens and germs. With these odds, we think it’s best to only rely on UV light as a supplemental form of air filtration. In other words, look for an air purifier that uses filters, for example, as its primary filtration system and UV light filtration as a bonus feature.

This Enviroklenz air purifier with UV-C light is a customer favorite, particularly for commercial spaces in need of long-term air cleaning. For more residential and affordable use, consider this Winix air purifier for small rooms. 

Air sterilizers are relatively new types of air cleaners that use heat to disinfect air as it passes through each unit. This process has been proven to kill at least 99% of airborne germs, bacteria, and allergens. Air is returned to room temperature before it is released back into your space.