[header] How to choose an air purifier for allergies [title] Choose a room air purifier. [step] This is your only option for an air purifier if your home doesn't have forced-air heating or cooling. These range in weight from 10-20 pounds, have a handle for moving, and stand on the floor or table in the room of choice. 
They generally cost less than whole-house models, ranging anywhere from $60 to a couple hundred dollars. [substeps] Room air purifiers require annual replacement of the filter that captures airborne particles responsible for allergies.