Air Purifier with HEPA Part II

The HEPA air purifier is the air purification industry benchmark, the standard by which other technologies are judged. "HEPA" is an acronym for “High Energy Particulate Arresting” filter.

This is the second part of the HEPA essay, folks needing the basics of HEPA purification technologycould visit the prior essay, "HEPA Filter Air Purifier Technology Explained", and use your browser back buttonto return here.

In the 60's we used to say "I'm hep", now it's "I'm heppa."

A true HEPA filter must remove 99.97% of airborne particles at .3 microns in size.

This is consideredthe "most penetrating particle size".

Smaller particles are considered to lack sufficient mass to penetrate the filter.

Principles of physics come into play, allowing filters with gaps between their fibers larger than .3 micron to capture particles down to .1 micron.

This model may be correct from a filter engineering standpoint, for high tech industrial and other cleanroom applications.

However, it does not fit well with less expensive residential air purifiers.

Household HEPAair purifiers as a group need to be considered in the light of particle passage, not necessarily penetration.

Time for a reality check: size does matter, only this time smaller counts for more.

Better quality air purifiers, HEPA or otherwise, will be able to certify particulate removal at sizes to .1 micron.

Lesser units bypass fine particles.

To avoid fine particle bypassing consistently, over the service life of the purifier, top quality components are required.

Again, to see this in action, check out the IQAir air purifier line.

This website did not start as a walking commercial for IQAir purifiers, a niche market with limited demand.

I could make triple the money parroting the party line and singing the virtues of lesser quality, but higher selling brands.

This would be a great disservice to my customers, the people who read and trust this site.

Of course, not everybody is going to run out and spring $1,000 bucks for these best HEPA purifiers.

IQAir is a goal to be aspired to, part of the upward social mobility we work to achieve.

The consumer can best understand the shortcomings of lower priced models and the application to their home environment by knowing quality and working down to a comfortable price range from there.

I believe quality HEPA filtration is required as the starting point for real air purifiers.

Some, notably Blueair, have achieved consistent HEPA grade performance but are not technically HEPA purifiers. Their design has some performance tradeoffs.

Others, notably the Friedrichs, formerly rated highly elsewhere (Consumer Reports), but cannot maintain .1 micron purification over the life of the air purifier.

HEPA Air Purifier

The HEPA air purifier is built around the motor, not the filter.

Several issues develop as a result.

Due to the static pressures built up ahead of sealed filters, stronger motors are required to build real purifiers with HEPA filtration.

An easy way around this is to intentionally let some of the pressure escape, bypassing the filter through tiny internal cracks and crevices.

Bypassing also assures adequate cooling air for cheaper motors without proper bearings. When true HEPA filters clog, they can reduce cooling airflow, increasing warranty claims costs.

If a larger filter were to be incorporated into the design, a bigger, more expensive motor would be needed. So cost issues confront engineers, who must build to marketing’s target price range.

What this means to buyers of residential HEPA air purifiers is that the majority of less expensive products on the market have glaring flaws which cannot be avoided.

Even the best will lack something.

I resolve this issue, which for me is serious (Multiple Chemical Sensitivity), by using several air purification products as a system.

Starting with cheap dust catchers, I add true HEPA machines, hydroxyl radical ionic air purification, and finally a premium HEPA with heavy carbon that I know I can trust.

Air purification devices currently running in my 750 square foot apartment;