Whisper-Quiet Hunter Fan. From the Hunter fan people...quietly improving your indoor air since 1886. HEPAtech® Ultra Quiet Air Purifier offers superior performance, design, and value. For guaranteed air purifier performance, look for the AHAM Certified, Clean Air Delivery Rate Seal. From air cleaner to air cleaner, compare the CADR numbers. First look at suggested room size. Then refer to the tobacco smoke, dust and pollen Clean Air Delivery Rate (CADR) numbers. The higher the numbers the faster the unit filters the air. This air cleaner is suggested for use in a single closed room up to 210 square feet. Room size ratings conform to the AHAM Certification Program criteria of 80% smoke reduction. Higher Clean Air Delivery Rates provide improved performance in all room sizes. Portable air cleaners will be much more effective in rooms where all doors and windows are closed. Smoke 136, Dust 151, Pollen 151. These values represent performances that can be expected within the first 72 hours of operation. Subsequent performance may vary with...