Dry winter air can wreak havoc on the body, causing a variety of cold and allergy symptoms. Dry air can also harm paint and wood furniture. While we cannot control the humidity level outdoors, we can use humidifiers to adjust the indoor humidity. Humidifiers are designed to increase the moisture, or humidity, in the air. Humidifiers also reduce the static electricity in the home, reducing the possibility of being "shocked." For best comfort and health, humidity levels should be between 30 and 50 percent.

Though there are different types of humidifiers, they all work by the same basic concept: water is placed in a holding tank and electronically sent into the air. Cool mist humidifiers, also called evaporative humidifiers, use a fan to blow water through a wick filter. The cool mist of water then evaporates into the air. Warm mist humidifiers, on the other hand, heat the water before sending it into the air. Cool mist versus warm mist is largely a matter of preference, although warm mist units generally make less noise. Warm mist humidifiers can also be used to dispense inhaled medications. In addition, warm mist units do not require a filter as the heating mechanism kills bacteria. On the other hand, it does require more energy to heat the water. Care should be taken when using warm mist humidifiers as they can prevent a risk of burns. Additionally, those in warmer climates may prefer the cool mist humidifiers as they cool the air.

Humidifiers also vary in size, water capacity, and area served. For instance, tabletop humidifiers, or room humidifiers, are small in size and are designed to be used in one room only. Tabletop models are available in cool mist or warm mist. Console models are larger units and are designed to control the humidity of multiple rooms. When buying a console humidifier, check the prescribed coverage area to determine its appropriateness for your space. All console humidifiers use cool mist, or evaporative, technology. Furnace humidifiers, as the name suggests, are professionally installed in the furnace ducts and are used to treat the entire house. Though more expensive initially, furnace humidifiers require less maintenance and are less expensive to operate annually.

It is important to clean and disinfect a humidifier regularly. Filters must be changed or cleaned as the manufacturer instructs. Failure to follow the care instructions for your humidifier could result in mold, mildew, and bacteria. The problems associated with those are much worse than the problems caused by dry air.

Another important consideration when choosing a humidifier is the humidistat. While low humidity can cause dry nasal passages, high humidity can cause the growth of bacteria and mold. A humidistat controls the humidity level and keeps it within an acceptable range. If you are unsure of your home's humidity level, a device called a hygrometer can measure it. Low-cost hygrometers are available at most local hardware stores.