Without a doubt allergies have long been connected to household dust stirred up by conventional vacuums. The HEPA filtration system traps the smallest particles that swirl about during house cleaning. So the vacuum works much more efficiently to trap microscopic particles that otherwise just become airborne then land again to repeat the same process over and over.

So here's the dirt. The primary cause is - well I might as well tell it like it is - dust mites and their poo. Folks who have allergic reactions from indoor contaminants don't like to admit that or may not even know that they are causing discomfort. Can't really blame them can you.

There are two HEPA's on the market. The absolute or true HEPA must be certified. But but for some odd reason there is a lesser version that's called a HEPA "type". No certification needed.

Let me explain. The absolute or true type is the real thing. Makes sense right? It must meet a rigorous testing procedure in which the standard particle size is .3 microns. That is microscopically tiny of course. And it must trap at least 99.97% of the little buggers.

Remember those dust mite droppings we were discussing earlier? Well, they are in the 1 micron range. The other HEPA type filter is called a, well, HEPA Type. They only have to catch those 1 micron particles 85 to 90 percent of the time. No certification needed.

Because they are so similar in appearance, you have got to examine them closely if you want a certified HEPA. It will be more expensive, have a certification number right on it and will tell you that it grabs down to .3 micron particulates 99.97 percent of the time.

If you want the best possible protection against indoor contaminants then consider a certified HEPA filter system.