A convection heater is a heater which operates by air convection currents circulating through the body of the appliance, and across its heating element. Convector heaters: Convector (or convection) heaters radiate warmth throughout the room. Like a fan heater, they have an internal heating element. However, instead of using a fan to circulate the warmth, they wait for hot air to rise and be replaced by cool air, which then gets heated.