This question comes up quite frequently in retail fireplace shops. To thoroughly answer this question, let’s start with a basic understanding of the way heat can transfer from one object to another.
THREE TYPES OF HEAT TRANSFER:
Heat is transferred from a warmer object to a cooler object through convection, radiation or conduction.
A typical forced air furnace will use convective heat to warm your home. A heat exchanger, normally made with steel or stainless steel, is heated up by burning a fuel. This fuel source could be gas, oil, wood or maybe even electricity. Once this heat exchanger is hot, a blower fan cycles on. As air is moved through the heat exchanger, this warm air is distributed throughout the house via the ductwork. Convective heat warms air and this warm air is moved through the house by the furnace fan.
Radiant heat is how the sun heats. Has this ever happened to you? You’re driving down the highway with the sun shining through one side of the car and not the other. The person sitting in the sun feels this radiant heat energy. But the person sitting next to you does not. That’s the radiant heat from the sun. Another good example is dining outdoors in a restaurant during a cool evening. Some restaurants use portable radiant heaters to keep customers comfortable while dining. The heat is delivered directly from a hot object to a cooler object through infrared radiation. Radiant heat, heats objects.
Conduction is the third type of heat transfer. Conduction is the movement of heat through a medium or passageway, from one object to another. A common example of conductive heat: Have you ever left a metal spoon in a pot of boiling water? It can get very hot as the spoon conducts heat from the water. With conduction, the temperature flow will always go from the hotter to the cooler object, in this case, from the hot water to the cooler spoon. Once the temperature is the same between the two objects, the transfer of heat stops.
SO HOW DOES THIS RELATE TO MY FIREPLACE OR STOVE?
Your fireplace or stove, whether it’s wood or gas, can be operated with or without an electric fan. Without a fan, you will get direct radiant heat from the glass and the cast iron or steel front of your fireplace. Without a fan, you will get radiant heat from the front, both sides, the top and even the back of a free-standing wood or gas stove. But by adding a fan to your appliance, you will enjoy convective heat in addition to the radiant heat.
HOW THE FAN WORKS
As room air moves through specially designed convective air chambers in fireplaces or stoves, heat is transferred from the hot surfaces to the moving air. The fan circulates this warmer air through the appliance and back into the room. Most fans on fireplaces and stoves use a rheostat to vary the amount of air the fan is moving. Turn the rheostat fan control up and a higher volume of air moves through the appliance. By turning the fan knob down, a smaller volume of air moves through the unit and less heat will be blown into the
room. Fan adjustments can be done manually. However, with many gas fireplaces and stoves today, adjusting the speed of the fan can be done with a multi-function remote control. It’s worthwhile noting that a fan will increase the heat transfer efficiency of your fireplace or stove.
Most blower fans on fireplaces and stoves will circulate air in the range of 75 – 250 cubic
feet per minute. On the low end of this range, that’s about the amount of air a bathroom fan will exhaust. Keeping the air moving in your house, even a small amount of air, will help maintain consistent temperatures throughout the house. It’s a good way to maximize heat output and help minimize cooler or warmer areas in the home.
ARE FANS NOISY?
Fireplace fans today are relatively quiet, especially on the lower settings. However, keep in mind whenever a fan is moving air, there will be some noise. Think about a calm day. It’s much quieter than a day when the wind is blowing 25 mph. It' the same with the air moving through your stove or fireplace.
Noises from fans other than air moving, for example squeaks, squeals or hums, often indicate a scenario that a dealer should get involved with. A problematic fan can normally be easily replaced.
An electric blower fan for your stove or fireplace will not operate, of course, in the event of a power outage. However, you will still get the benefit of the radiant heat. If reliability of power is a concern to you, or if you are off the grid, there are specific models of stoves and fireplaces designed to be strictly radiant heaters.
It’s also important to periodically inspect the fan and clean any dust, dirt and pet hair from it. Incidentally, the fans of fireplaces are located behind the lower grill. Blower fans on free-standing stoves are found on the back of the unit.
So, the question comes up again: Do I need a blower fan on my fireplace or stove? It’s all about comfort, based on your preferences. That being said, most WE LOVE FIRE experts are big fans of fans!