What CADR rating do you need for a kid's bedroom air purifier?
Match the CADR (in CFM) to about two-thirds of the room size in square feet for asthma-grade results.
What's actually in it
CADR stands for Clean Air Delivery Rate. It tells you how many cubic feet of clean air a unit puts out per minute. A purifier that's too small for the room cycles air too slowly to drop particle counts. For asthma-grade results, you want the unit to swap the room's air about five times per hour.
What the research says
A 2026 study in Pediatr Pulmonol placed real HEPA air cleaners in homes of kids with severe asthma. Families saw fewer flares, better sleep, and more good days. Units that worked were sized to the room. A simple rule: match CADR (in CFM) to two-thirds of the room's square footage. A 150 square foot bedroom needs at least 100 CADR.
Look for "CADR" on the box and check the room rating. Brands like Coway Mighty, Levoit Core 400S, Blueair Blue Pure, and Honeywell HPA300 publish CADR clearly. Run the unit 24/7 on low. Replace HEPA filters per the schedule. Pair with sealed HEPA vacuuming and damp dusting.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Installing Air Purifiers in the Homes of Children With Severe Asthma | Pediatr Pulmonol | 2026 |
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