True HEPA Filtration

Does Your Vacuum Make You Sick?

Now, I'd like to point out the differences between TRUE HEPA filtration and all other types of HEPA when describing residential vacuums. I'm very proud to say that an old timer in the vacuum business taught me about these differences. I've looked all over the internet for information about this. I could not find anything that really explains WHY some residential vacuums are rated TRUE HEPA and some are just rated HEPA.

For starters, a few things need to be in place for TRUE HEPA vacuums to get that rating. The heart of the vacuum, the motor, has to be powerful enough to pull the dirty air into the collection unit, through the HEPA filter and continue to push the clean air back into the room. It seems easy enough on paper but these TRUE HEPA filters are highly restrictive as they must trap 99.97% of particles over .30 microns in size. If you're not familiar with microns, I'll make it a little easier for you to understand exactly what we're dealing with here. The period at the end of this sentence is about 300 microns, which is 1000 times bigger than the particles that a TRUE HEPA filter will contain.

If you'd like to see a chart that shows a list of common particles and their sizes in microns click common particles in the home.

The power of the motor can be found in two specifications: CFM which stands for Cubic Feet (of air) Per Minute. This is the amount of air pulled through the vacuum. AMPS which is a measure of electrical power, defines the amount of power used by the motor. I've found that usually these ratings go hand in hand when it comes to service quality, so if one is not available you can use the other. Please be advised: even if the vacuum meets the ratings I've just mentioned, the airflow THROUGH THE FILTER is much more important. We'll get to that in just a moment. Our backpack vacuums move approximately 150 CFM and draw about 9 AMPS. This is a good reference for you to use if you'd like a high quality TRUE HEPA vacuum.

Once you've found a vacuum that is capable of moving the air properly, you need to take a close look at the construction. Most importantly, the placement of the HEPA filter in relation to the motor. The only way the filter can be effective enough to capture 99.97% of all particles larger than .30 microns is if it's placed BEFORE the motor's exhaust. Please bring your attention to the diagrams on your right paying particular attention to the airflow.

In the diagram pictured on top, the vacuum pulls in the dirty air above the filters (there are 3). The air first travels through a paper filter which is HEPA rated. It then travels through a cloth HEPA filter. The air is now clean enough to leave the vacuum at .30 microns but before it does, it is filtered through a cone HEPA filter for a final cleansing. The air then travels through the motor and exits through a foam exhaust filter which is not HEPA rated.

In the diagram shown below, the vacuum pulls in the dirty air. It travels through a long intake tube, through a collection tank which is not HEPA rated but just separates large particles. The air then travels through the motor and exits through a HEPA rated filter.

Here's what the old timer taught me: If the motor is powerful enough to get the air into and out of the vacuum and if the HEPA filter is placed AFTER the motor, the power of the airflow will push the filter AWAY from the housing and let dirty air escape back into the house without being filtered. The main filter(s) MUST be placed BEFORE the motor!