See larger image Honeywell 50250 99.97% Pure HEPA Round Air Purifier (Kitchen) List Price: $210.99 USD New From: $164.89 In Stock Used from: $89.99 In Stock Release date September 15, 2005.

• What is a hepa filter?

• What is the very best hepa air purifier available?

• What about filter costs?

Hepa air purifiers have been around since the mid 1940s. They were in fact developed by the U.S. Government for the atomic bomb program during WW2. They needed a very exacting filter to protect the workers for airborne atomic particles. So then what does the word hepa even mean anyway?

No Official Standards for Hepa Air Purifiers

Would you believe that hepa is an anitialism for the words (high efficiency particulate air)? Also would you believe that there are no real official standards that govern how exacting a hepa filter has to be? There are however, accepted norms in the industry that dictate a filter of this type must stop 99.97% of particles .03 microns and above in size.

What About 99.97% Down to .01 Microns?

This is why you may have already noticed that most common hepa air purifiers, for the most part stick to these specifications. So then can you buy an air purifier that uses this type of filtration system that can do better than that? You bet you can but bear in mind that filters in general are balancing act.

The Better the Filter the Higher the Cost

That is the tighter their specifications and the smaller the particles they remove, the more expensive they tend to be. So how expensive can they get? Very expensive as a matter of fact, with some of the better filters costing several hundred dollars.

Filters that Cost More than the Machine??

A $250 30 pound air filter for an Austin Air Healthmate.

In fact if you have to make sure to check the actual cost of the filters and how often they need replacing on any air cleaning system you are considering. This is because it's not at all uncommon today for the cost of filter changes in some machines to exceed the actual cost of the machine, over a couple of years time.

To Change or to Vacuum - That is the Question

Another thing to consider, if your have severe allergies is what the actual changing of filters on any hepa air purifiers entails. You see some models will advertize that that their filters only require a vacuuming, rather than a complete change-out. For someone with severe allergies though this dusty job may be out of the question.

99.995% is Pretty Much Everything in the Air!

So then just what is the efficiency rating of the all time best hepa air purifiers that are available? Those would be medical grade commercial air purifiers. The type you would find filtering the air in an operating room. They go all the way down to an amazing 99.995%.