Understanding CADR Ratings
The Clean Air Delivery Rate (CADR) is a standardized measurement used to evaluate the effectiveness of home air purifiers. CADR values represent the volume of air (in cubic feet per minute) that an air purifier cleans of particles like smoke, pollen, and dust, covering a range of small to large particle sizes. In 2024, a new PM2.5 CADR standard was introduced, focused on particles smaller than 2.5 microns, calculated from the smoke and dust CADR scores.
Certified Air Purifiers for Reliable Performance
The CADR rating program, managed by the Association of Home Appliance Manufacturers (AHAM), ensures air purifiers maintain performance standards through independent testing. This certification helps consumers compare products based on both air flow and filter efficiency, providing a reliable benchmark for choosing an air purifier.
Why CADR Matters
The CADR value combines air flow and filter efficiency, offering a balanced view of an air purifier’s effectiveness. For example, a high-efficiency filter with low air flow would have a lower CADR, ensuring buyers aren’t misled by efficiency claims alone. This balance is especially helpful, as some brands highlight high filter efficiency without considering air flow.
EnergyStar CADR Report
In the U.S., CADR is expressed in cubic feet per minute (CFM), while some regions use cubic meters per hour (m³/h). Be cautious, as m³/h numbers appear larger but don’t directly compare with CFM values. The CADR standard is integral to ENERGY STAR® certification, with requirements linking CADR to energy efficiency, setting standards for air purifiers sold in the consumer market.
For instance, if an air purifier has a CADR of 250, it should consume 86 watts or less at high speed. With a 250 CADR, it’s suitable for spaces up to 387.5 sq ft (using a multiplier of 1.55 for coverage).
| Smoke CADR Range | Minimum Smoke CADR/Watt |
| 30 ≤ CADR < 100 | 1.9 |
| 100 ≤ CADR < 150 | 2.4 |
| CADR ≥ 150 | 2.9 |
How CADR is Measured
CADR tests use the highest fan speed on new, clean filters, which may not reflect performance over time. Smaller filters may perform well initially but may decline quickly. For long-term efficiency, consider models with larger filters and more media to sustain CADR performance as filters age. Note that CADR does not account for noise levels or safety features like ozone production.
Choosing an Air Purifier Based on Room Size
For effective air purification, match the CADR rating with your room size. Using the “two-thirds rule,” multiply your room's square footage by 0.67 to find the minimum CADR needed for adequate coverage. For instance, a 300 sq ft room requires an air purifier with a CADR of at least 200.
Summary:
The CADR (Clean Air Delivery Rate) rating is a standardized metric that helps consumers compare the performance of air purifiers. It measures how much clean air is produced on the highest fan speed, capturing particles like smoke, pollen, and dust. CADR values are certified by the Association of Home Appliance Manufacturers (AHAM) to ensure reliable performance. This rating combines air flow and filter efficiency, offering a balanced view of how well an air purifier will work in various environments. Additionally, CADR is used in ENERGY STAR® certifications to set energy efficiency standards for air purifiers, helping buyers make informed choices based on room size and air quality needs.