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What is a Wood Stove Fan?

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  • Written By: Michael Pollick
  • Edited By: Lindsay D.
  • Last Modified Date: 27 July 2014
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A wood stove fan distributes heat from a wood burning stove throughout the rest of the home. Some fans are electric, but more recently the trend has been towards self-powered fans that work on heat alone. The added expense of running an electric fan many be nominal, but some owners have discovered that electric motors and radiant heat sources don't always mix well. Early stove fans tended to malfunction after constant exposure to unregulated heat and fire.

Wood stoves work on the principle of radiant heat, much like the fireplaces they may have replaced in homes. A crackling fire in a typical fireplace may look attractive, but much of the useful heat is lost up the chimney or trapped in the ceiling airspace. A ceiling fan may send some of that heated air back to the living area, but it adds to the electric bill and may not be very efficient.

A solid metal wood stove, on the other hand, is designed to become a radiant heat source. Very little heat energy is lost up the chimney, which also becomes a source of radiant heat. The difficulty with such a system, however, is even distribution of that heat. Those sitting near a hot stove may feel comfortably warm or even hot, but others may experience cold spots and drafts. One solution to this problem is to use a fan.

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Manufacturers of wood burning stoves incorporate hollow metal tubes around the body of the stove. These tubes have adjustable vents on one end and an opening for an electric blower on the other. Early wood stove fans resembled industrial-strength hair dryers, with a side turbine providing airflow into the tube, and the owner's only options were "on" or "off." The electric blower would force the heated air through the vents and into the room. This did provide a better exchange between hot and cold air levels, but the added utility expenses and potential for accidental meltdowns negated the money-saving benefits of a wood burning stove.

A recent innovation in wood stove fan technology actually reached into the past for a more energy-efficient solution. Modern fans use the radiant heat from the stove to heat hot air in the engine, sometimes referred to as a Sterling Engine. A piston turns the blades of a fan, which is responsible for blowing the excess heat above the stove into the living space. The parts of a self-powered fan are engineered to withstand the high temperatures of a wood burning stove, so the possibility of a meltdown is significantly reduced. No additional electricity is needed to run it, so the savings in energy costs are measurable over a three or four month winter season.

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Discuss this Article

anon215048
Post 18

Rising energy costs have prodded Americans to buy not only more fuel-efficient cars, but also wood pellets, which generally are made from sawdust and wood shavings, as fuel to heat their homes. About 800,000 homeowners are already using them.

anon151191
Post 15

so what is it people, so many different opinions. if i point my fan at my stove, the air on the other side is -- wait -- fairly hot. how could this be wrong? if i put my fan on the other side of the stove, it is cold. who is wrong here, people?

I'll keep on trying new stuff until i find a "best" place. but a fan will help when pointed at the stove, in my opinion. there has to be some real science to it and none of us have found it as proof, or is proof, like in most cases, our own opinion?

anon137071
Post 14

Build a metal cabinet around the wood stove leaving a 2" to 4" space from the floor. I left the front open and built tightly around the stove in this area. Leave the top open or also cover it, leaving smaller openings that can be ducted to floor registers. This creates a natural draft "chimney" effect in the cabinet.

I have fabricated the above and works very well increasing the heat and better directing of the heat into the living space instead of over heating the cellar.

anon136826
Post 13

Any time you lower the air temp around the stove by fan or whatever it will increase the thermal transfer and the efficiency, because the greater the differential the greater the transfer.

anon136823
Post 12

If the stove smokes while the fan is on, it is creating a vacuum or negative pressure in the room or stove, this pulls air out of the stove. Put the fan on the floor and blow air into the heated room. This will cause a positive pressure in the heated room.

anon136821
Post 11

I have done some testing on this, putting a fan on the floor next to a doorway and pushing the cold air from the cold area toward the stove or into the heated area will give the best distribution throughout the house.

anon126172
Post 10

why does the house smell like wood smoke with a fan in use? my daughter is renting a house and is having real problem with her stove. She now has to use electric baseboard heat, and you know what that means: money. could you help if i gave more info? eg: stove brand, design, etc?

anon119923
Post 9

using a fan blowing at the stove is similar to how a forced hot air furnace works. by convection, the blower used in the furnace distributes the hot air where you want it, rather than just accumulating in a small area, so in both cases, a fan or blower will make the room warmer!

anon104007
Post 8

The heat powered stove fan is designed to circulate warm air created by multi fuel stoves. It works without batteries or mains. You can buy from Eakers or Crediton.

anon59564
Post 7

Lots of arguments about how not to do it. Any one have positive solutions to offer? Move fan to a different location for a night. Was it warmer, or not? If not, move it again.

Lowering the BTU's by 1,000 or 2 (at your metal surface) seems like a decent price to pay for bumping the temp in distant rooms by a couple degrees. What good is a billion BTU if it doesn't keep your toilet seat warm two rooms down?

anon55276
Post 6

The above post -anon21376 is not true. By blowing air across the surface of the stove, you lower the temperature of the steel. This allows better heat transfer from the fire to the metal because it is a larger delta T between the fire and metal. Otherwise, the heat does not transfer to the metal and has nowhere to go but through the chimney.

anon54257
Post 5

Moving air over a hot surface will distribute heat more uniformly throughout the room. Whether air flows towards or away from the stove makes little difference.

However, cooling the exhaust can reduce the flow of combustion air through the stove.

Heat transfer from the fire to the stove surface is radiant; from the surface to the room is convection.

A fan will help increase the convection heat transfer coefficient and increase the amount of heat from the stove into the room.

bridgerman
Post 4

I have a fan on a stand behind my stove. I heat my home in Montana almost exclusively with wood. The post above about not being able to generate more BTUs is correct...however when I use my fan blowing into my stove, the stack temperature drops dramatically. So in effect, what is happening is that less heat is being wasted through the chimney and is being applied to heating the house.

That being said, blowing cool air over the stove will get more heat out. Trying to suck heat from the stove with a fan in front, in my opinion, will just change the shape of the heat plume rising from the stove, not get more heat out.

I also have friends using a product called ThermGuard to move the air around the entire house. It connects to your thermostat and turns on the furnace fan only which draws the air warmed by the stove into the furnace air return and blows it into the back bedrooms. It lowers the temperature in the room with the stove and raises the temperature in the bedrooms.

anon23304
Post 3

I'm arguing with my mom about the best way to distribute heat from her wood stove, using a regular fan.

She insists on pointing a fan AT the woodstove to circulate the heat. I believe that would push the cool air in room to stove and simply 'scatter the heat' without 'creating flow'.

On the other hand, I suggest:

"put the fan in front or above the stove, and point it AWAY from the stove, in order to create air flow from room to stove to room.

Who's right, or are they equal in effect? Pattie

anon21376
Post 2

It is not possible to use a fan attached to the woodstove which will cause the stove to convert the energy in wood more efficiently or transfer the available energy from the burn area to the exterior surface. Stove design is primary factor in this.

Blowing air across the hot metal surface(more cfm's) will not get one more heat(btu's), only lower btu's at greater cfm.

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