Why Use a Humidifier in the Winter
Winter means dry indoor air, a result of lower humidity outside and blowy heating systems inside. Adding cool or warm moisture to the air by using a humidifier has many benefits: easier breathing, a diminished chance of suffering winter ills such as colds and respiratory infections, furniture and other indoor items will not dry out as much, the air will feel warmer, plants will stay fresher longer, and your skin and throat will not be as dry. The best benefit, as far as I'm concerned, is that moist air helps avoid the unpleasant "zap" you often get from static electricity.
If your home is more than a few rooms, invest in two or three humidifiers and keep them filled. Be sure to follow the manufacturer's recommendations for filter maintenance and changing as well as for how often and how to clean the water reservoir so as to avoid mold and bacteria buildup.