Is a ducted range hood better than a recirculating one?

For actual air quality, decisively: ducted hoods remove moisture, grease, odors, and combustion products from the house, while recirculating hoods filter grease and some odor and return everything else, heat, moisture, and gases included, to the kitchen.

What CFM range hood do I need?

Working rules: at least 100 CFM per linear foot of range against a wall, more for high-output and gas cooking, with capture geometry, a deep hood mounted at spec height and covering the burners, mattering as much as the number.

Do recirculating hood filters actually work?

The grease mesh works when washed; the charcoal layer adsorbs some odor while it is fresh and does nothing once saturated, on a replacement clock of months that almost nobody keeps. Neither removes moisture or combustion gases.

Does a big range hood need makeup air?

High-CFM hoods can depressurize tight houses enough to backdraft combustion appliances, which is why codes require makeup air provisions above set thresholds, commonly 400 CFM. The hood and the furnace room are one system.

Range Hoods: Ducted vs. Recirculating

Page last reviewed: August 2026 · Reviewed by Harold R. Bennett, retired home inspector

Cooking is the largest routine indoor-air event in most homes, searing and frying generating the fine particles, moisture, grease aerosol, and, on gas ranges, the combustion products that the indoor-air roster ranks near its top, and the range hood is the appliance assigned to it. The ducted vs ductless range hood question is therefore an air-quality question with an honest, lopsided answer, and the interesting work is in the details: capture, CFM, duct rules, and making the best of the ductless case. This comparison covers all of it.

The honest gap

Ducted hoods capture the cooking plume and exhaust it outdoors: moisture, grease, particles, odors, and gas combustion’s CO and NO2 all leave the building, which is the entire definition of exhaust ventilation doing its job. Recirculating (ductless) hoods pull the plume through a washable grease mesh and a charcoal odor layer and blow it back into the kitchen: grease is meaningfully captured, odor partially and temporarily (charcoal saturates on a clock of months), and everything else, the moisture that feeds the condensation-and-humidity economy, the fine particles, the combustion gases, returns to the room, filtered in name. The gap is not a brand or price problem; it is physics, and the practical conclusion follows: duct wherever ducting is possible, treat recirculation as the constrained fallback it is, and treat a gas range under a recirculating hood as the specific combination that deserves the most skepticism, per the combustion-safety logic.

Capture and CFM: the design half

A hood works by catching the plume before the room does, and geometry beats horsepower: a hood covering the burner area (full width, ideally with overhang), deep enough to catch the front burners, and mounted at the specified height (commonly 24 to 30 inches over electric, 27 to 36 over gas, per the unit’s label) captures at modest airflow what a shallow, high, undersized hood misses at any CFM. The airflow rules of thumb then size the fan: at least 100 CFM per linear foot of range at a wall (so 300 for a standard 30-inch), more for high-BTU gas and serious frying, island hoods higher still for their exposed plume, and microwave-hood combos flagged honestly as the category’s weakest captures. Two system notes complete the design: noise (sones) predicts use, exactly as with bath fans, a roaring hood being a hood turned off; and makeup air is the big-CFM hood’s legal and physical companion, codes commonly requiring provisions above 400 CFM because a powerful hood in a tight house depressurizes it, pulling air down flues and backdrafting combustion appliances, the interaction that makes the hood and the mechanical room one system.

The duct rules

Ducted performance lives or dies in the run: smooth metal duct at the hood’s specified diameter (reducing a 7-inch hood onto a 4-inch duct strangles it), short and straight as the structure allows, joints foil-taped, terminated outdoors through a damper-equipped wall or roof cap, never into the attic (the attic-moisture indictment applies with grease added) and never a screened outlet that mats shut. Grease writes the maintenance schedule: mesh filters through the dishwasher monthly, and the duct’s own interior on a multi-year professional cycle in heavy-frying households, hood-duct grease being a real fire-load item the dryer-vent logic rhymes with.

Making the best of ductless

Where ducting is genuinely impossible, rentals, interior-wall kitchens, high-rise units, the recirculating case is managed rather than solved: buy the best capture geometry available, wash the grease mesh monthly and replace the charcoal on its actual schedule (the failure mode of the entire category being ten-year-old charcoal), run the hood on high through and after cooking, crack a window while frying to give the plume somewhere to go, lean on the HVAC filter and any HEPA unit for the particle share, watch kitchen humidity, and, on gas ranges specifically, keep the CO alarm honest and the future ducting question alive, since a remodel that opens a path to outdoors is the upgrade that actually closes the gap.

The bottom line

Ducted removes the problem; recirculating rearranges it. Size the hood to cover the burners at spec height, give it 100 CFM per foot and a full-size smooth metal duct outdoors, provide makeup air past the code threshold, and wash what the grease touches. And where the duct truly cannot exist, run the fallback hard, change its charcoal like it matters, and let the window do the part the filter never could.