It is better to perform air purifier ratings by yourself rather than rely on what other people and other companies come up with. But before you go out on your own, you have to look at ten basic principles in rating air purifiers.

First is check if the manufacturer offers a return policy. A return policy is period of time given to the customer so the he can judge if he is satisfied with the product or not.

Second is to identify the type. There are six types of air purifier namely ozone generators, ionizer, electrostatic precipitators, electret type, HEPA type and the HEPA.

Third is to check the size of the filter. The bigger the filter means more clean air coming through.

Fourth is the efficiency of the air purifier.

Fifth is the number of times the air purifier changes air within an hour. The safe number of times an air purifier changes air in an hour is from four to six times.

Sixth is the cost of the filter. Normally those air filters that people buy separately may even be more cost efficient for the long haul.
Seventh is the ease of replacing filters.

Eighth is look for an indicator to change filters.

Ninth is the ability to remove stench.

Tenth is to look for a warranty.