CADR is the most important number on an air purifier spec sheet—and most people ignore it completely.
CADR stands for Clean Air Delivery Rate, and it tells you exactly how fast a purifier cleans the air in your room. It’s the difference between a purifier that actually works and one that looks impressive on paper but leaves your room still dusty and hazy.
Let me walk you through CADR, show you how to match it to your room, and highlight the best air purifiers at each CADR level.
Table of Contents
Air Purifiers by CADR Rating
What is CADR and Why It Matters
CADR measures cubic feet of clean air per minute (CFM). A purifier with CADR 300 means it’s cleaning enough air to completely refresh a 300 sq ft room once per hour.
Higher CADR = faster air cleaning. A CADR 500 purifier cleans the air twice as fast as a CADR 250. For allergies and asthma, faster is better—faster air exchanges mean fewer allergens staying in the air.
The trick is matching CADR to room size. A CADR 150 purifier won’t help much in a 500 sq ft living room, no matter how good the filter is.
CADR by Room Size
Small Rooms (100–200 sq ft): Target CADR 75–150. This includes bedrooms, home offices, nurseries. A Levoit Core 300 (CADR ~200) or Coway AP-1512HH (CADR ~290) work great here.
Medium Rooms (200–400 sq ft): You need CADR 150–300. Living rooms and master bedrooms fit here. Blueair 411 (CADR ~325) is perfect—fast enough to clear a room in one air exchange cycle.
Large Rooms (400+ sq ft): Aim for CADR 300+. If your living room is 500+ sq ft, don’t compromise. IQAir HealthPro Plus (CADR ~400+) or dual-unit setup gives you the coverage you actually need.
Best Purifiers by CADR Range
CADR 150–250 (Budget/Entry-Level)
These work fine for bedrooms and small apartments. Air changes take 2–3 hours in a medium room, which is slower but still effective. Levoit Core 300 is the standout here—surprisingly high CADR for the price.
CADR 250–400 (Mid-Range/Best Value)
This is the sweet spot. Blueair 411 hits CADR ~325, giving you solid coverage for 400+ sq ft rooms without premium pricing. Coway AP-1512HH and Winix WAC9500 land here too.
CADR 400+ (Premium/Medical-Grade)
For whole-house coverage or severe allergies/asthma. IQAir HealthPro Plus delivers CADR 400+ and can clear a 1,000 sq ft space. It’s expensive but worth it if air quality is critical to your health.
Final Word
Don’t buy an air purifier without checking the CADR rating first. Match the CADR to your room size, and you’ll get a purifier that actually works. A $1,000 unit with low CADR will underperform a $400 unit with high CADR in the same room.
For detailed comparisons of specific models, see our best air purifiers guide and price tier breakdown.
