interior heater means: An electrical device which is placed on one’s car and that, when connected to an electric socket with a plug, heats the inside of the vehicle like a space heater. It can be used in all parts of the globe where temperatures drop below freezing. You can set the interior heater to turn on at a specific time or even keep it warm in extremely cold conditions. It’s usually identified as an electric cord that sticks out under the car’s hood in Canada and the border states. (in Community Dictionary, added by Ashton Boyer)