A heater blower is a device attached to a heating unit that helps to distribute air throughout a vent system or move it in a specific direction. Unlike standard fans, blower fans often have multiple blades designed to move air quickly with little effort.
A heater blower can usually be set to different speeds, or it can be connected to a thermocouple switch. When the desired temperature is reached, the fan switches off to save electricity or gas. Usually, it's intended to move air through a large area, so it has to increase speed and pressure to send the air through vents.