How Do Electric Heaters Work?

Electric Heater Basics

All electric heaters use electricity to provide heat, and most of them turn electric energy directly into heat via a heating element. The manner in which they distribute this heat, however, varies quite a bit from heater to heater. Convection heaters heat the air, while infrared heaters heat objects in the room directly. Heat pumps work like refrigerators in reverse, actually taking outside heat and moving it into a room.

Convection Heaters

Convection heaters are the most common type. They are powered by a heating element made out of a material called a resistor that resists the flow of electricity. An electric current contains a tremendous amount of energy, and that energy gets turned into heat when it flows through the heating element. Many convection heaters simply heat the air directly above, causing that air to rise and spread out around the room. Other heaters, called forced air convection heaters, speed up the process of warming the room by blowing air over a heated coil with a fan and out into the room.

Radiative Heaters

Radiative heaters use heating elements at much higher temperatures than convection heaters. The heating elements are usually encased in quartz crystal or some other protective covering that doesn't allow the heat to escape, keeping the element extremely hot. At such high temperatures, the element emits waves of infrared radiation. These infrared waves do not warm the air very much, but when they encounter an object, they warm it up. An infrared heater can be used to directly warm up people, keeping them warm even in a drafty environment.

Heat Pumps

Heat pumps use a pump to drive a liquid called a refrigerant through two sets of coils: a condenser coil and an evaporator coil. The compressor first compresses the refrigerant and drives it into the condenser. As the pressure increases, the liquid gets very hot. It flows through the condenser coil inside the house where a lot of its heat is transferred into the air, warming the room and cooling the refrigerant. It is then decompressed in the evaporator coil outside the house or underground. This causes the refrigerant to get very cold. The outside heat then warms up the refrigerant again, and it flows back to the compressor. In this way, the heat pump continuously takes air from outside and pumps it inside the house.