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Outside / Ducted - The polluted air rises, is pulled up by a fan, passes through filters, and is exhausted outdoors through a metal duct. High BTU gas cooking equipment should always be ducted to the outside of the home. Inside / Non-Ducted - A fan draws the polluted air through filters and then recirculates the cleaned air back into the kitchen. Non-vented hoods circulate the air through charcoal or other filters fitted in the house and then let out purified air for recirculation.
Ducted or Vented hoods
Aluminum Mesh Filters - Designed to trap grease before the smoke and odors are forced outside. Filters require periodic cleaning and many are dishwasher safe.