why does an heater with a fan is more efficient than a similar heater that doesn't have a fan?

It distributes the heat throughout the space (room) that is being heated.

An heater with a fan is more efficient than a similar heater without a fan because it distributes the heat more effectively throughout the space that is being heated. Let me explain the reasoning behind this.

When a heater without a fan is operating, it relies solely on the natural process of convection to distribute the heat. Convection is the transfer of heat through the movement of air or fluids. In this case, the heater warms up the surrounding air, and as the hot air rises, it moves towards the ceiling. As a result, the temperature near the ceiling is higher than near the floor, creating uneven heating.

On the other hand, a heater with a fan utilizes forced convection. It has a built-in fan that blows the heated air into the room. The fan helps to circulate the warm air throughout the space, creating a more uniform distribution of heat. This means that the temperature will be more consistent from floor to ceiling, and the whole room will warm up faster.

In summary, the fan in an heater improves efficiency by evenly distributing the heat throughout the room, avoiding hot and cold spots. This leads to more effective and quicker heating, resulting in improved comfort and potentially energy savings.