How do you determine the best home air purifier allergy machine? It all depends on:
"Which kind of allergies do you have?"
That's because different allergies call for different technologies: Pollen Allergies- HEPA air filters are the first choice because they actually catch and hold the pollen. Allergists recommend HEPA above all others.
Pet Allergies - For animal dander HEPA is also the first choice. If you have cats and dogs a washable "pre-filter" is also a good idea because it catches animal hair and extends the life of the HEPA filter.
Mold Allergy- To kill mold you'll need something that actually kills the mold. Negative ion and Ozone are best because they actually go out into the room to kill mold. Despite claims that HEPA helps with mold it does not kill mold, it only catches mold spores.
Dust Allergies- HEPA again is best to catch particles like dust.
Mildew Allergies- Negative ion and/or ozone kill mildew.
Smoke Allergy- Here's where carbon, electrostatic and/or ionization can be an affordable way to reduce smoke. These technologies are less expensive than HEPA.
Chemical Allergies- If you are chemically sensitive to chemicals then carbon or zeolite is the ideal technology. That's because carbon and zeolite will absorb the chemicals. Hepa will not, Uv will not, nor will electrostatic (although it can sometimes disable some of the gases in the air).
There are three problems with whole house air purification systems (which use the duct work of the existing A/C and Heating units):
1) The fan power that would be needed to pull enough air through the intake vents would waste a lot of electricity and hot/cold air.
2) Duct systems are not designed to circulate air, but rather to deliver hot/cold air.
3) Smaller units are much less expensive to maintain, circulate the air more efficiently and work much better.Of course to keep vents clear of dust regular changes of the systems filters is a must. For this I recommend the Filtrete Ultimate Allergen Reduction Filter (ON SALE HERE). It's preferable to a regular cheap filter.