Air Purifier CADR Coverage Comparator
AHAM Verifide is a real independent test: a lab measures a purifier's Clean Air Delivery Rate (CADR) for smoke, dust and pollen, and AHAM's own sizing guidance is a "2/3 rule" — a room's tobacco-smoke CADR should be at least two-thirds of its square footage, which works out to 5 air changes an hour in a room with an 8-foot ceiling. We fetched five brands' own current product pages directly. Three of them state a real CADR number and pass AHAM's own math. All five also print a second, much bigger coverage number on the same page — computed at 1 air change an hour instead of 5 — and for most of them, that's the number stated first.
The headline number, checked against the brand's own CADR
This table doesn't depend on what you typed above. For each brand's stated CADR, we compute what AHAM's own 2/3 rule (5 ACH, 8 ft ceiling) would say the honest coverage is, using the identical CADR x 8 ft ÷ (2/3) arithmetic AHAM's own rule is built from — then compare it to what the brand's own headline number actually says.
| Brand | Stated CADR | AHAM 2/3-rule coverage (computed) | Brand's own headline claim | Gap |
|---|---|---|---|---|
| Honeywell HPA300 | 300 CFM (smoke (dust 320, pollen 300)) | 450 sq ft | 465 sq ft (4.8 ACH — stated explicitly on their own page) | 1.0x bigger |
| Levoit Core 400S-P | 231 CFM (particle type not labeled on this page) | 346.5 sq ft | 1,718 sq ft (1 ACH — stated explicitly on their own page) | 5.0x bigger |
| Coway Airmega Mighty AP-1512HH | 224 CFM (smoke (dust 248, pollen 232)) | 336 sq ft | 1,680 sq ft (1 air change/hr — stated explicitly on their own page) | 5.0x bigger |
| Shark Air Purifier MAX HP202 | no CADR of any kind stated on this page | Not computable — no CADR published | 1,200 sq ft (1 air change per hour — stated explicitly on their own page) | — |
| GermGuardian AC4825 | 99 CFM (smoke (dust 118, pollen 125)) | 148.5 sq ft | 743 sq ft ("every hour" framing — the same 1-air-change math as the others, worded differently) | 5.0x bigger |
Check your own room against each brand's stated CADR
Enter your room's square footage above; this section applies AHAM's own 2/3 rule directly.
What this does not do
- It does not independently re-measure any CADR figure. All five numbers are each brand's own current stated value, not a repeated third-party test of the specific unit sold today.
- It does not apply AHAM's 2/3 rule to Levoit's 231 CFM figure with full confidence about particle type — Levoit's own product page states one CADR number without labeling whether it's smoke, dust or pollen CADR, and AHAM's rule is specifically about tobacco-smoke CADR. The 231 figure is used as printed, with that caveat stated plainly.
- It cannot check Shark's HP202 against AHAM's own rule at all — Shark's own page states a square-footage claim but no CADR of any kind, so there is nothing to run the 2/3-rule arithmetic on.
- It does not adjust for ceiling height, pollutant type, or how "clean" a reader wants their air — AHAM's own 2/3 rule is itself one fixed assumption (8 ft ceiling, tobacco smoke, 5 ACH), not a law of physics.
- It compares one representative current model per brand, not every purifier each brand sells.