If you purchase a Broan range hood vent insert with one of our range hoods, the range hood opening will be crafted perfectly for the insert at no extra cost. 21" Custom Built-In Vent Insert: Design your dream kitchen with the custom insert range hood that can be built-in to cabinets Powerful Ventilation: Quickly remove smoke, odors and cooking pollutants with the 450 Max Blower CFM ENERGY STAR Certified: Save energy costs and have powerful ventilation Bright 1-level, heat resistant LED modules enhance your cooking experience Easy access 3-Speed rotary controls make operation easy Dishwasher-safe aluminum mesh filters feature quick-release latch for easy removal Works with optional stainless LB30SS and LB36SS liners Optional non-duct recirculation kit and filters available for indoor exhaust recirculation to suit your needs along with optional built in vent. CFM, which is the measurement unit for exhausting air flow, stands for cubic feet per minute. The higher the CFM number, the greater the amount of air that is exhausted when using the range hood.A sone is an internationally recognized measurement unit for loudness that can provide an accurate indication of what humans can hear. If the number of sones is doubled, the loudness of a noise is also doubled (i.e., if a unit produces 2 sones of noise and another unit produces 4 sones, the second unit is twice as noisy as the first).One sone is equal to the soft hum of a refrigerator in a noiseless kitchen.
