Tabletop units can usually handle only single rooms. Larger console models can be set up in central locations to distribute moisture to a large area of the house. Humidifiers are recommended for people who live in areas where houses must be heated for a good portion of the year. Humidifiers will help those suffering from sore throats, headaches, nosebleeds and coughs related to dry air. In general, a moist house is more comfortable than a dry one.
People tend to put water in it, turn it on and forget about it.
As a result, you may cause a health problem, rather than eliminate one. All units, portable as well as those installed in central heating systems, must be cleaned rigorously. Otherwise, they tend to become contaminated with mold and bacterial growth that may be blown through the house. Dr. Waite recommends cleaning portable units every two weeks and central units once a month. He suggests removing any residue, then letting a solution of chlorine bleach sit in the basin for 30 minutes to kill any fungus or bacterial growth.