Types

Types of air purifiers in the High-Efficiency Particulate Air filter category, also called a HEPA filter, include electrostatic, ionic, smoke and whole house air cleaners. Reviewing and rating entities such as Consumer Reports and Air Purifier Ratings evaluate air purifiers separately within the type and all types together.

Ratings

The Association of Home appliance Manufacturers has a voluntary program. Maximum clean-air delivery rate, abbreviated as CADR, and the appropriate room is included in this program. The CADR is a measurement of cleaning speed, and a rating of excellent is at 350 or above to poor at 100 or below. A reporting value known as the minimum efficiency reporting value, or MERV, and developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers is another rating used by Consumer Reports in evaluating air purifiers.

Features

Air purifiers utilize different filters and purification technologies based on the models and manufacturer. Electrostatic precipitator air purifiers charge pollutant particles to remove them from the air, but a byproduct of this is ozone. This ground-level ozone has the potential to be an irritant to some people who suffer from asthma or other respiratory infections. Ratings of the features on purifiers aid in identifying undesirable aspects.

Ranking

The general purpose of a rating of a product is to determine the overall best product of the group. This is usually based on a ranking system of qualities inherent in the product along with customer comments. The Air Purifier Rating organization uses a point system based on the efficiency of the filter system, how easy the purifier is the operate, the air flow and consumer feedback. At the time of publication, Air Purifier Rating put Oransi v-hepa Finn Air Purifier at the top of the list with a 9.0 overall rating.