True HEPA Home Air Filters

How HEPA Air Purifiers Can Help Improve Indoor Air Quality

Many air conditioning and heating experts recommend adding an air purifier to your home to filter out allergens and other undesirable particles from your indoor environment. For allergy sufferers, that means installing a HEPA air purifier, as the indoor atmosphere is often more polluted than the outdoors because of recycled air.

HEPA is an acronym that stands for High Efficiency Particulate Air. Filters used in a HEPA air purifier must meet a designated standard, meaning that they must be able to remove at least 99.97% of airborne particles measuring 0.3 microns in diameter. Particles of that size are about 300 times smaller than the width of a human hair. See the manufacturer site for details.

All air purifiers, including those with HEPA air filters, work by circulating air through the unit. When the air encounters the filter, the filter prevents the particles from passing through. HEPA filters look like folded papers inside an air purifier. The air moving quickly through them traps the undesirable particles in three different ways:

• At high air speeds, dust and other particles smash directly into the filter.
• Fibres at the edges of the filter snag even more particles as they try to pass.
• At lower air speeds, undesirable particles tend to wander about in the purifier, where the filter's fibres eventually snare them.

If you are considering a multipack of HEPA filters, make sure that they are made of fine glass threads with a diameter of less than one micron. The glass threads are tangled and compressed to trap dust mites, bacteria and other undesirable particles. Make sure that the filter meets HEPA manufacturing standards. Packages designated as true HEPA filters will always indicate that the contents will trap at least 99.97% of airborne particles. Some multipacks will trap higher concentrations of particles, which should also be noted. The lower the MERV (Minimum Efficiency Reporting Value) rating, the more efficient the filter will be.

Allergists recommend air purifiers with HEPA filters because these devices are more efficient at removing allergens and other particles that irritate the nasal passages and airways of allergy and asthma sufferers. HEPA air purifiers are efficient at removing these types of substances:

• Dust mites
• Many varieties of pollen
• Mould
• Bacteria
• Viruses