You should take several factors into account when choosing an under-cabinet range hood.
Size of Cooking Surface
In order to have the most useful impact possible in your kitchen, your under-cabinet range hood should be the same width as your cooking surface. This will allow your range hood to catch and funnel the grease- and smoke-filled air you want to filter and potentially vent from your home. Though it won’t be an issue if your range hood is a little bigger than your cooking surface, if your range hood is too small it will not be able to filter all the air you want it to.
Because under-cabinet range hoods are installed under, well, cabinets—which typically do not extend to cover the entirety of your cooking surface—you should focus on finding a range hood to match the width, not depth, of your stove. Under-cabinet range hoods are designed to take this smaller size into account and can still provide adequate ventilation so long as width requirements are met.
Size of Cabinets
Because this type of range hood is installed underneath existing cabinets, it’s imperative that you have enough cabinet space to accommodate it. In addition to the unit itself, you will want to leave a width of two to three inches on either side for ideal ventilation. You will also need enough space nearby (e.g. in the walls or ceilings) for any ductwork and vents that accompany the range hood system.
Airflow (in CFM)
The CFM (cubic feet per minute) rating on all range hood products refers to how much air the unit can process, filter and remove at once. A higher airflow will give you a speedier (but not necessarily better) ventilation than a lower airflow rating. The best CFM for you will depend on the size of your kitchen and your cooking style. For example, if your cooking produces a lot of heat, grease and smoke, it may be better for you to have a range hood with a high airflow.
Exhaust Timers
If your under-cabinet range hood comes equipped with this feature, it simply means the fan will turn off after a certain amount of time (typically 10 minutes). This feature is useful if you want to leave your range hood running even after you finish cooking but might not have a chance to or might not remember to turn it off.
Fan Settings and Speeds
All range hoods should have, at the bare minimum, two fan speeds: low and high. The low setting is quiet and best used to clear the air while finishing or just after cooking. The high setting is best used while in the process of cooking, especially if you are generating a lot of smoke, steam or grease. A third speed is often included, offering a middle ground between the more extreme settings. More than this is typically not necessary for a domestic kitchen.
Ducted vs. Ductless
If your under-cabinet range hood is ducted, it means the air processed by the range hood will be vented outside (through a ductwork system). A ductless range hood will simply vent back into the kitchen after filtering. Make sure you know which system you want for your home—while a ductless unit is not as effective as a ducted system, it is convenient for a smaller kitchen or home or for those who do not cook often.
