The earliest Chambers ranges were small, but all were constructed of heavy gauge steel and porcelain enamel. All models were thickly insulated, which enabled their owners to use them like an ordinary range or cook using retained heat. To help owners of their products learn the proper use of the retained heat cooking feature of their ranges, Chambers developed a large home economics department in their Shelbyville, Indiana, factory. There, recipes and cooking times using the insulated properties of their products were carefully tested and perfected. These tests resulted in charts which indicated the amount of time - and at what temperature - the gas was to be burned in the oven and the Thermodome (which was succeeded by the Thermowell), before it was to be turned off completely while the food continued to cook on retained heat. By 1927, Chambers published a cookbook for the homemaker to not only help her learn how to care for and operate the appliance, but also to assist her in menu planning, proper table setting, etc. This publication was called The Idle Hour Cookbook. The Idle Hour Cookbook was replaced in the late 1960s by Rangaire with an actual operation manual. Chambers promoted the ranges using traveling cooking shows. John Chambers' daughter Alma Chambers, traveled coast-to-coast for over twenty years conducting large cooking shows to promote the Chambers Range.