Ductless range hoods are one of three different types of range hoods, along with ducted, or vented, range hoods and convertible range hoods. Vented range hoods require access to outside from the area in the kitchen where the stove is located. Convertible range hoods can be used with either ductless or ducted systems.
Versions that are ductless are usually the second choice in range hoods. When it is possible to install a hood that can be vented to the outside, that will be the more popular choice, since they expel stale kitchen air directly outside. If the stove is located near a window or against an exterior wall, then installing a vented range hood is a relatively straightforward process. The range hood must be vented outside; it cannot be vented into an attic or an interior wall.
If a kitchen stove is located along an interior wall, or for some other reason a homeowner cannot install a vented range hood, he or she will probably choose a ductless model instead. Ductless range hoods work differently than vented range hoods: they do not pull kitchen air outside, but rather filter the air and then release it back into the home.
A ductless range hood will not work without a clean air filter. Many use charcoal filters, which make an excellent choice for cleaning the air in a kitchen, because they absorb odor and other residue that can make the kitchen smell unpleasant. If the hood has an exterior aluminum filter, the homeowner will not have to replace the filter, but it will need to be cleaned.
Whichever type of filter the range hood has, it is important that homeowners check it every three to six months. A dirty filter will not only make the range hood less effective, it will also make the motor work harder, shortening its life.
Ductless range hoods are not as effective at cleaning the air in the kitchen as vented range hoods, but for many people, they are the only reasonable option. If the layout of the kitchen prohibits the addition of a vented range hood, then a ductless one can be a good choice. As long as the filters are cleaned or replaced on a regular basis, this version is a very effective way to keep a kitchen smelling fresh.