How Do Convection Space Heaters Work?

Convection Heater Basics

Convection space heaters generate heat in the same way that an electric range or electric oven does. Electricity flows through a resistor--a material that resists the flow of electric current. The resistor turns the electric energy into heat energy. In the case of convection heaters, this heat energy is then distributed through the room through convection, along with conduction and forced air.

Convection

When a hot object is in a room, It heats the air immediately above it. This heat causes the air to expand, which makes it rise. As it rises, the warm air creates a vacuum, pulling in other cool air behind it. That air is then heated, repeating the process. This causes a continuing convection current, circulating warm air around a room and eventually heating the whole space.

Conduction

Many convection heaters also employ conduction to heat the air. When an object is hot, its molecules are excited and move quickly. In a solid object, these molecules bang into nearby molecules, passing the heat through the entire object. Some materials such as metals are particularly good conductors, quickly passing heat on.

Conduction in Convection Heaters

The more surface area a heater has, the more air it can heat simultaneously. That is why many convection heaters are shaped like steam radiators. They have fins coming off the main body, allowing them to heat the air between the fins and over the entire heater. This can create much more effective convection currents, quickly spreading the heat.

Forced Air in Convection Heaters

Some small, portable convection heaters actually rely on forced air more than convection. In these heaters, a blower fan blows directly on an extremely hot coil, blowing hot air out into the environment. These heaters can produce a lot of heat with a very small size and distribute it pretty quickly. On the downside, they are fairly dangerous, because the heating element is exposed. If they are placed too near to flammable objects, these heaters can sometimes cause fires.