Electric Wall Heaters  Electric wall heaters are designed to heat one room at a time. The most common ones are  fan forced wall heaters which help heat the room quicker. You will notice the fan typically  goes in reverse which pulls the cold air in then goes through an electric heating element and warm air will shoot out the bottom part of the grille with the discharge temp of about 130 degrees F will flow into the room.. The Electric wall heater is controlled by either a built in thermostat, wall mounted thermostat or wall mounted timer... A built in thermostat is the most common way to control an electric wall heater because its the easiest to install. To operate it you turn the knob clock wise this will turn the power on then you set the desired temperature.. There is a return air sensor in the built in thermostat that measures the current air temp. Once the air temp is the same set point on the built in thermostat the unit will turn off.. Wall mounted thermostats for electric heaters are a option as well but are not as common because the installation is a little harder because you have to run an extra wire across the room.. there is line voltage and low voltage thermostat. and mechanical and digital thermostats in those two styles