Home Air Purifiers: How to Compare the Models

Efficiency Rating

• The Association of Home Appliance Manufacturers certifies purifiers based on appropriate room size, maximum clear-air delivery rate (CADR), and minimum efficiency reporting value (MERV). CADR is judged on a scale ranging from 350 to 100, 350 and above being excellent, and 100 and below as poor. The MERV scale was developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, and ranges between 1 and 10; top performing purifiers usually carry a score above a 10.

Types

• Room air purifiers are portable and cost less than models that are built into a home. A room purifier is equipped with a HEPA filter, which captures ultra fine particulates like pollen and dust. You must replace a HEPA filter annually, and replacement filters can run upwards of $20. Whole house iar purifiers are built into the forced air heating of a home and can cost thousands of dollars. Some whole house purifiers have an electronic precipitator. These precipitators can produce ozone, which can deposit pollutant particles into the walls and soil them.

Features

• Most room air cleaners use a fan to suck in air, which runs louder than models that do not have a fan. Models without a fan do run quieter, but their maximum clean air delivery rate is much lower than units that include a fan in the design. Servicing indicators allow you to monitor how efficiently your air purifier is running. Servicing indicators also alert you to when you need to clean or replace the filters depending on the model.