What Is HEPA?

Arguably the most misunderstood concept of a vacuum cleaner is that of HEPA. We could spend a large amount of time trying to provide a lot of information, but our intent is to give an overview and cut through the clutter to supply you with a useful guide to HEPA filtration.

During WWII, scientists developing the atomic bomb needed to devise a means of filtering small, not able to be seen particles. Out of this desire the HEPA standard was developed. HEPA is an acronym for High Efficiency Particulate Air. The HEPA standard demands that 99.97% of all particles (.3 microns or larger) must be captured by the filter media.

That is a very exact standard. Let’s also be clear on something. You and I are unable to see anything that is .3 microns in size without a microscope. For most people without respiratory issues, this is not an issue. But for people with allergies or respiratory problems this can be at the least, irritating, and at worst, life threatening.

We are going to address the misconceptions around HEPA filtration in vacuum cleaners. HEPA and the standard (and even more stringent standards) are used in many parts of our society. Hospital operating rooms, clean rooms and other very sensitive areas will use HEPA filters to keep the environment ultra clean.

Many vacuum cleaners claim HEPA in their literature and advertising. Unfortunately, since there is no governmental agency looking out for consumers as it relates to this claim, most of the time the public is being hoodwinked.

Remember, HEPA is not a filter…HEPA is a standard! How then can manufacturers claim to have a HEPA vacuum? Remember we said that HEPA stands for High Efficiency Particulate Air? What if a manufacturer decided that HEPA means Highly Effective Particulate Air? He can still use the acronym HEPA for his filter but not meet the HEPA standard. Deceptive? Yes. But, technically true.

There are 2 classes of HEPA Filters: S-Class and C-Class filters.

S-Class Filters
These are the most common type of HEPA filters. They were made as a prototype and tested in a laboratory for efficiency. During the test, the filter is exposed to a flow of air and a specific particulate count. Air exhausting the filter is measured for content and receives a pass or fail grade. If it passes, the prototype is awarded a certificate number.

Armed with the certification number, vacuum manufacturers insert these filters in a variety of designs and then claim that their vacuum is HEPA. Some even say that the system is “SEALED” to add credibility to the claim. However, our experience and tests show that many of the designs are poor and the dirty air leaks through seals or cracks in the housing or joints of the vacuum.

Another factor that affects the HEPA claim is that often these low cost S-Class HEPA filters are tested at a relatively low air flow, say 30 CFM. Putting a HEPA filter tested at 30 CFM into a vacuum producing 80 CFM will no longer emit clean air. Technically it’s HEPA, but the air coming out of your vacuum isn’t. So, you think you’ve gotten the HEPA standard when you buy one of these vacuums, but you haven’t.

C-Class Filters
C-Class filters are individually tested, and each one is given a certification number. C-Class filters are made better and out of much higher cost materials. And when making the jump to a higher quality filter, the manufacturer almost always designs and builds a vacuum that has a sealed compartment, ensuring that dust and dirt will not escape around the body and seals, and that all exhaust will exit through the HEPA filter. Many of the vacuums are further tested to ensure that the entire vacuum cleaner meets the HEPA standard, not just the filter.

What about HEPA vacuum bags? Remember when I said, “Highly Effective Particulate Air”? Remember what I said about airflow? The same thing applies. Make no mistake, though. The softer cloth-like HEPA bags do filter better than paper style bags. They do such a good job that they actually extend the useful life of many HEPA filters because they are filtering smaller particles that would have otherwise clogged the HEPA filter. Remember, a vacuum bag IS part of the overall filtering system of your vacuum.

In conclusion, most of the shouting about HEPA is marketing hype to get you to buy a cheap vacuum and make you feel like you’ve done something that will really clean your home. If you question whether or not a vacuum, or YOUR vacuum, is HEPA, then bring it to our store, and we will use our particle scanner to show you whether or not your vacuum is HEPA. And if this is important to you, we can show you a vacuum that will produce air that is HEPA clean.