Ventilation - Duct vs Ductless / Roof vs Wall

Ducted

A ducted range hood removes heated air by forcing or exhausting air outdoors, effectively removing it from your kitchen space. Ducted range hoods are more effective than their ductless counterparts, and they, too, vary widely in price. Ducted range hoods operate by drawing in cooking air and then directing it outside your home through either a wall vent or, in some cases, upwards through ceiling joists and the roof.

The National Kitchen and Bath Association (NKBA) provides optimal ducted range hood installation guidelines. It recommends that these hoods be airtight, boast smooth interior surfaces, feature a backdraft damper, and remain separate from all other exhaust systems. Furthermore, the exhaust from these systems should be expelled outdoors and not directed toward spaces like attics, soffits, ridge vents, or crawlspaces. The NKBA emphasizes the necessity for cooking surface appliances to be equipped with appropriately sized ducted ventilation systems, with a minimum of 150 cubic feet per minute (CFM). A minimum exhaust rate of 100 CFM is deemed necessary for ducted hoods for effective operation.

Ductless

A ductless hood uses a filter that removes smoke and odor from the air above the cooking appliance and returns it to the room. Unlike ducted hoods, a ductless hood does not vent the air outside your house. The fan within a ductless range hood pulls in air and circulates it through a charcoal filter, which traps grease and certain odors. It's important to note that this method is not as efficient as a range hood that expels air outside.

Ductless range hoods are commonly found in compact homes or apartments and are notably more affordable than their ducted counterparts. They also offer the convenience of being DIY-friendly for installation. The filters within ductless range hoods gradually wear out over time as they clean and recycle the air, necessitating replacement approximately every three months to maintain optimal performance.

Roof vs. Wall

The preferred trajectory for ductwork is up and outside your house, ideally leading through the roof to the exterior. If circumstances prevent venting above the hood, an alternative route is through a side wall. When designing the ductwork, aim for the shortest and most direct path, minimizing the need for bends and turns. By doing so the smoke and grease produced during cooking encounter the smoothest, least obstructed route as they navigate through your kitchen and exit your home.

Your range hood type will determine whether it can be vented through a roof or wall. Chimney and island hoods necessitate ceiling and roof venting, respectively. In contrast, wall-mounted hoods provide the flexibility of horizontal venting through a wall aperture or vertical venting through the ceiling. It's crucial to avoid terminating ductwork in the attic to prevent the accumulation of exhaust within that space.

An alternative avenue is a centralized, whole-house ventilation system driven by a robust motor that draws air from multiple locations. This setup reduces noise levels, as the fan motor is located in the attic rather than within the kitchen's wall or ceiling. This alternative configuration can contribute to a quieter and more efficient ventilation process throughout your living space.