Our team of experts periodically post questions they are asked and their answers so that others may benefit from the information.

Q: What is a HEPA filter, and do I need one?

A: While consumers increasingly are requesting HEPA filters, many do not understand what this level of filtration efficiency means or how it differs from filters labeled "high efficiency."

HEPA filters capture 99.97 percent of household dust, pollens, bacteria and many allergens as small as 0.3 microns or 1/300th the diameter of a human hair. Many irritants are larger than 0.3 microns, and therefore, are large enough to be captured by HEPA and high efficiency filters:

Bacteria (0.3 microns), pet dander (0.5-11 microns), pollen (7 to 100 microns), plant spores (9 to 100 microns), and even some cooking (0.3 - 30 microns), wood (.03 - 3 microns) and tobacco smoke (.01 - 1 micron) (Particle Size Source: North Central Regional Extension Publications, Cooperative Extension, U.S. Department of Agriculture)

Consumers need to understand that filtration efficiency is only half the story. How the filter affects vacuum cleaner performance is the real test of customer satisfaction. A HEPA filter in itself may not lead to optimal vacuum performance. If it's made of microfiberglass or paper, it can clog easily, and deteriorate over time, thus reducing the vacuum cleaner's airflow, suction and cleaning ability.

Also, look closely at some vacuum cleaner or vacuum cleaner filter packaging. Be wary of terms, such as "HEPA-Like" or "HEPA-Rated Filter Media." While these terms may imply HEPA performance, if it doesn't directly say HEPA filter, it's probably not. Many elements go into making a filter that delivers HEPA performance - the efficiency of the media, the filter's construction and how it seals inside the vacuum cleaner housing, among others. A filter labeled "HEPA-like" may not deliver the performance you're expecting. Read labels carefully.

Q: What type of vacuum filter works best?

A: Surface filters, which stop particles at the surface of the filter, are the most efficient filters available. Surface filters prevent filter clogging while preserving maximum airflow through the filter and ensuring optimum suction power with each pass of the vacuum.

CleanStream® filters, made with a space-age polymer and engineered with composite membrane technology, can stop particles at the surface of the filter while resisting permanent clogging. The particles can be easily tapped away clean from the surface of the filter, restoring like-new airflow and efficiency.

Both types of CleanStream® filters - those installed in household vacuum cleaners as well as those sold as replacement filters for wet/dry or "shop" vacs - are surface filters.

However, most vacuum cleaner filters on the market today are depth filters, which draw and capture particles inside the filter. Eventually the depth filter becomes clogged, reducing airflow through the filter, which can compromise its performance and potentially shorten the life of the vacuum cleaner. Fine particles that reach the motor can cause overheating and wearing down of the vacuum's mechanical parts through dirt and dust buildup. If not changed frequently, these conventional filters can even stir and spread dust and dirt throughout your home. If you or someone else in your household has allergies, you may want to avoid using conventional vacuum filters.