Most rangehoods can be formatted to either be ducted or recirculating. Ducted setups vent steam and odours to outside and are the usual preference. However, sometimes ducted setups are not possible when the kitchen is not against an external wall, or if exterior aesthetics would be compromised. In these circumstances, a recirculating setup will absorb the smoke and odours and expel filtered air back within the house.
Canopy rangehoods have a large overhead hood and are effective in catching a lot of smoke & odours. They are visually dominant which may or may not be preferable. Island rangehoods are designed to not need a wall behind.
Downdraft rangehoods are built-in to the countertop and raise as needed. They are great for islands where a canopy is not desired. Surprisingly efficient with steam, they’re not ideal for heavy odours. They are expensive even before benchtop installation.
The most discreet of all rangehoods, the undermount is near invisible. They are shallow because of wall unit depth limitations, so are better suited to situations where strong-odour cooking is infrequent. They handle steam well enough. They can be very cost effective.
Compact and very affordable, a slide out range extends the hood depth by telescoping outwards. They are not as effective as canopies but slightly more effective than undermount.