About HEPA Filters
Most air purifiers use a HEPA filter. HEPA (High Efficiency Particulate Air) filters are the most efficient mechanical filters available on the market today, and are capable of removing very small particles from air that can be inhaled deep into the lungs. The system uses a fan to draw room air through the HEPA filter. The HEPA filter then traps airborne particles passing through the filter such as smoke, dust, pollen and pet dander.
HEPA technology was originally developed by the U.S. government. The highest efficiency systems typically remove 0.3 micron (1 micron = 1 millionth of a meter) sized particles at a minimum rate of 99.97% efficiency. In a 99.97% filter, for every 10,000 particles passing through it an average of only 3 would pass all the way through.
Many systems also feature a "pre-filter", which cleans the air before it is passed through the HEPA filter for maximum cleaning power. These pre-filters, which typically last between three and six months, can also help extend the life of a HEPA filter. Under normal circumstances, the HEPA filter itself will last eight months to one year.
We carry a full assortment of replacement filters for the air purifier models we sell. We recommend storing replacement filters in their original packing until they are needed.