AHAM Verifide explained
The Association of Home Appliance Manufacturers runs a voluntary certification program for portable air cleaners. A unit that carries the AHAM Verifide mark has had its Clean Air Delivery Rate measured by an independent laboratory under a published standard, ANSI/AHAM AC-1.
How the test works
The unit runs at top speed in a sealed test chamber. Smoke, dust and pollen are introduced in turn, and instruments track how fast the particle concentration falls compared with natural settling in the same chamber. The result is three CADR figures in cubic feet per minute, plus a suggested room size at the rate of 4.8 air changes an hour. Units are retested periodically, and the makers pay for the program.
Why it matters
A manufacturer can print any CADR on a box. Uncertified figures are frequently measured at a higher fan speed than the unit ships with, in a smaller chamber, or in cubic meters per hour presented as if they were cubic feet per minute (a 1.7× difference). Certified figures are consistent with each other, which is what makes a ranking possible.
That is why certification carries 10 percent of our score: an AHAM-listed unit receives full marks, a claimed-only unit receives 30 percent. The AHAM Verifide list ranks only certified units.
What it doesn't cover
AHAM measures particles, not gases, so it says nothing about carbon or odors. It measures at top speed, so it says nothing about noise. And a unit can be excellent without being listed: some makers skip the program, and some tested units are sold under other names. The independent measurements on model pages fill in what certification leaves out.
Checking a listing
The directory at ahamdir.com lists every certified model with its three CADR figures and room size. If a maker claims certification and the model isn't in the directory, treat the CADR as a claim.