Recirculation Venting Vs. Roof Venting

Recirculation Venting

• Recirculation venting constitutes a closed system. It takes air from an indoor environment, passes it through a filtration system then reintroduces it into the environment. Recirculation venting systems do not contain ducts that connect to the outside. These systems appear most commonly in kitchens, where they take hot air coming from stoves and ovens, clean it through a filtration system then reintroduce it into the kitchen. Kitchen recirculation venting usually comes in the form of a vent hood that installs directly over a stove.

Roof Venting

• Roof venting helps control the airflow and moisture content in a building through vents placed on a roof. Roof vents expel unwanted air from an internal environment while helping remove moisture that may potentially damage construction materials, such as wood, cement or metal. Roof ventilation systems interact directly with exterior forces, including wind and weather. In cold climates, poorly designed roof venting can introduce frost into the attic of a building. In warm climates, poorly designed roof venting can lead to extremely hot conditions in attics, resulting in overworked air conditioning systems and high energy bills.

Fundamental Difference

• The fundamental and distinguishing difference between roof and recirculation venting arises from the interaction, or lack thereof, with exterior environments. Roof venting interacts directly with exterior environments, connecting to it through vents and ducts. Recirculation venting, on the other hand, connects to nothing. As self-contained systems, recirculation vents and vent hoods interact only with air in indoor environments that comes into direct contact with the vent itself. Roof venting deals with air from indoor and outdoor environments.

Other Differences

• Roof venting comprises a system composed of multiple parts, including ducts and vents. Recirculation vents, on the other hand, constitute a single vent or vent hood with an intake fan, filtration system and exhaust fan. These vents only interact with air that requires some kind of filtration -- installers place them very deliberately in buildings to take advantage of this function. Conversely, roof venting provides general ventilation assistance and connects to other systems in a building, such as heating and cooling.