per ISO 3744—to ensure the dBA reading is accurate and comparable between brands. Certification : Organizations like the Home Ventilating Institute (HVI)

The phrase "sone to dBA verified" refers to the process of converting a perceived loudness measurement ( ) into an A-weighted decibel level (

There is no single fixed ratio for this conversion because sones are linear and dBA is logarithmic, but industry standards generally use the following benchmarks: is approximately equal to (roughly the sound of a quiet library). is approximately equal to 28–30 dBA (similar to a quiet refrigerator). is approximately equal to (a calm office environment). is approximately equal to (normal face-to-face conversation). Why "Verified" Matters

0.3 sone is 22.5 dBA, so they are the same. This link will help. 0. Tom's Hardware How is Sound Measured? - NIDCD - NIH