Corningware crockpots are very energy efficient, using only as much energy as a 60-watt light bulb. This means that even over the long cooking times required, it uses much less energy than a conventional oven or hob. The insulating effect of the Corningware helps to enhance this property.
The Corningware crockpot works best if the food is browned or heated before being placed in the dish so that it brings some heat with it, and foods with a high liquid content, such as stews, are the most convenient type of crockpot recipe, as they do not require stirring or readjustment. However, no liquid is lost during cooking by this method, so it's also important to make sure that the bare minimum of liquid is used initially to allow for more fluids coming out of ingredients as they cook.
In order to maximise energy efficiency when using a Corningware crockpot, it's important to leave the lid on throughout the cooking time. Removing the lid allows heat to escape and reduces the effectiveness of the pot. Many Corningware crockpots have removable dishes that allow the finished product to be browned off conventionally at the end of cooking, but this uses additional energy.