What ducted exhaust actually changes
When a hood is routed to the outdoors with a continuous, leak-aware duct path, particles and gases that enter the hood can leave the building—assuming capture is sufficient at the cooktop. That is the core distinction: exhaust relocates the pollutant outside the breathing zone. Performance still depends on CFM, static pressure, and duct quality, and on capture geometry so the hood actually pulls the plume.
Cold-climate installations sometimes add complexity: condensation in vertical runs, cold-weather backdraft behavior, and the need for caps that exclude pests without choking flow. Those are not reasons to avoid ducting; they are reasons to plan transitions and termination carefully with qualified installers.
What recirculating hoods can and cannot do
Ductless (recirculating) hoods draw air through grease separation stages, then through charcoal or similar adsorbent media. Grease management remains critical—see filters, grease, and fire sense—because flammable residue still accumulates near heat.
Charcoal beds capture some odor molecules and certain gases through adsorption, but they do not replicate the mass removal of true exhaust. Media saturates, pressure drop rises, and fan noise can increase without a proportional increase in perceived air quality. That is why filter life indicators deserve skepticism—replacement schedules should be conservative, not optimistic.
When recirculating is a rational compromise
Rentals, historic retrofits, and high-rise constraints sometimes make ducting impractical or prohibited. In those cases, a well-maintained recirculating hood with disciplined filter changes is still far better than no capture at all—especially if users run the fan during high-heat cooking and keep grease trays clean.
The honest framing is: you are choosing between degrees of mitigation, not between “perfect” and “useless.” The more aggressive cooking you do indoors, the more you will feel the difference between filtration and exhaust.
Interaction with whole-house pressure
Large ducted hoods can depressurize tight homes—especially when combined with other exhaust devices. If you are considering a very high-flow ducted hood, read makeup air and depressurization alongside this article. Recirculating models reduce some of that pressure concern but introduce maintenance burden instead.
Choosing without shame, upgrading with a plan
If you are shopping, start from the physics: capture first, then flow and duct—or filter—capacity. If you already live with a recirculating hood, optimize behavior: preheat with the fan on, clean metal filters on a schedule, replace charcoal media before saturation, and revisit whether your hood geometry matches your actual burner use.