Written by: Will Housh
Indoor Air Quality Expert and President of DiscountFurnaceFilter.com

What Is HEPA? An Introduction to HEPA Filtration

At DiscountFurnaceFilter.com, we highly recommend that you consider a HEPA filtration unit, whether portable or central, for your home or business. HEPA filters provide the absolute best performance at filtering airborn particulates down to 0.3 microns or smaller in size. HEPA filters can be very effective for people with allergies or asthma since these ailments are often triggered by inhalation of airborn particulates that HEPA filters can eliminate.

HEPA air filters are not MERV rated as they exceed the ASHRAE test protocol 52.2 used in determining the MERV ratings. In fact, HEPA air filters are the ONLY mechanical air filters that are tested and certified to meet a specific efficiency at a specific particle size. All HEPA air filters must meet a minimum efficiency of 99.97% at 0.3 microns. ASHRAE or MERV air filters are tested using the Dust Spot tests that incorporate some fine dust, powdered carbon and some cotton linters. The Dust Spot test particle size range is from .3 microns to 50 microns in size with an average size of approximately 20 microns in size.

HEPA air filters are tested using DOP, Mineral Oil and other materials that generate a mono-dispersed particle that are all .3 microns or smaller in size. In essence, if 10,000 .3 micron sized particles are blown into a HEPA air filter, only 3 particles are allowed to pass through. Thus, you get the 99.97% at .3 micron rating. If you were to use the HEPA test on a 95% ASHRAE air filter they would be about 50% efficient on .3 micron sized particles once they loaded up with dust. So, HEPA air filters are at least 50% more effective at removing respirable sized airborne particles than any of the ASHRAE air filters on the market. To review our selection of HEPA filters, Click Here.

If you need any more information or have any questions as you consider an indoor air quality purchase, please do not hesitate to contact our customer support team via email by clicking here: I Have A HEPA Question

As always, Thank You for shopping at DiscountFurnaceFilter.com. We sincerely appreciate your business.

Will Housh
Founder and President
DiscountFurnaceFilter.com