A do-it-yourself house humidifier is being marketed nationally by Comfort Enterprises of Leola, Pa., a division of the 30-year-old Herrmidifier Co. Inc. in Lancaster, Pa.

Called Good-Bye-Dry, the product is designed to be installed into any forced warm air heating system. It is being sold for about $69.95, according to executive vice president Roger Dickinson. Outlets include home centers, hardware stores and other related businesses catering to homeowner needs.

Dickinson said that new install-it-yourself humidifier is different from other Herrmidifier models because its plumbing connections are made in the factory. He said that the buyer does have to attach one self-piercing valve to any water pipe and also cut a hole in the heating system's hot air ductwork, onto which the humidifier is placed. He said that reports from buyers on warranty cards indicate that they were able to install their humidifers in about an hour.

Dickinson said that a federal study showed recently that homes with humidification systems experience energy use savings of 5 to 15 percent when compared with homes without humidification.

Dickinson's pamplet on humidity and central home humidifiers is available by sending a stamped, self-addressed envolpe to Roger Dickinson, Comfort Enterprises, Box 323, Leola, Pa. 17540.

Dickinson is one of the seven men who bought the Herrmidifier company three years ago from founder Paul Herr.