An exhaust hood system consists of three main components: a skirt or capture panel to contain the rising gases (also known as the “effluent plume”), one or more grease filters, and a fan or tangential blower for forced ventilation.

There are two major configurations of extractor hoods: ducted (or vented) application, and ductless (or recirculating) application. In a ducted application, the output collar of the extractor hood’s blower motor is attached to a duct system, which terminates outside the building. In a ductless application, a filter, often containing activated charcoal, removes odor and smoke particles from the air before releasing the cleaned air back into the kitchen. For commercial, ducted type of exhaust hood is the most suitable to be used.

A ducted system allows for removal of all forms of airborne contamination, while a ductless one recirculates heat and moisture into the kitchen. In addition, a ducted application eliminates the need for regular replacement of the filters, and avoids the airflow restriction (and resultant loss of power) caused by them. However, ducted application does have disadvantage, due to lack of space or ability to install a duct system, make-up air requirements, or the additional cost of heating/cooling the make-up air. Some range hood designs allow for both types of applications.