As fall rolls in, people start to dread the cold winter months and the cost to keep the house warm. Fireplaces are very pretty and cozy but are actually very inefficient. This instructable will show you how to get alot more heat out of your fire place for about $50 (cost me only $30 because I had scrap wood, old computer fan, and an AC to DC wall transformer).

Step 1: Supplies

Gather/Buy the following items:

- Flexible Automotive Exaust Pipe

I used 2.5 Inch diameter pipe that was 6Feet long from Advanced Auto parts. You can get this at almost any automotive store. Its thick but flexible metal pipe that is made to deal with High Temperatures

- Computer Fan

The fan will be used to force air through the exhaust pipe.

- AC-DC Transformer (Wall Wart)

If you wan you can buy one of these from Radio Shack, but most people have these laying around from old electronics. The Only thing to keep in mind is that the voltage rating should be Less than or Equal to the voltage rating on the Computer Fan.

- Scrap Wood

This will be used to adapt the fan to the exaust pipe

- Aluminum Tape

This helps assembly the wood box and seal the pipe to the wood adapter box.

Step 2: Wooden Adapter Box

Now we will create a box that will take the air from the fan (which is normally a rectangle or square) and push it down the exaust pipe (which is round).

1) Cut your wood so it is all 6 Inches wide.

- We will then cut it to match the length of each side of the fan.

2) Measure the sides of the Fan

3) Cut the wood to match the lenghts of the fan.

- Should have 4 pieces in the end. If you want to get a bit more fancy you can cut some lengths a bit longer so that after we assembly all for sides the fan will fit snug inside.

4) Using the aluminum Tape Attach all 4 side to create the rough Square.

OPTIONAL - If the Fan you are using is very large or the pipe you are using is very small, you may want to cut one last piece of wood that will place on the back of this square of wood and then cut a hole in it that will accept the pipe.

Step 3: Wire Up and Add the Fan

Now we need to get the fan spinning and attach it to the wooden box.

Take the Wall Wort power supply (ac to dc transformer) and cut the ends of the wires to your required length.
Strip the ends of the wires.
In Order to get the fan to spin in the proper direction, this next step may take some trial and error.
1. Attached one stripped wire from the transformer to one of the wires from the fan by twisting the wires together and using electrical tape for insulation. Then repeat this for the second wire.
2. Fans are designed to rotate in a specific direction and will blow more air if they spin in the correct direction. This direction is normally marked on the fan (or the direction that the wind should be blowing). Plug the transformer into the wall and see which way the fan is spinning and blowing air. This instructable is assuming you are using a DC fan, so if the fan is spinning in the wrong direction, flipping the wires should correct this.
Once the fan is going in the correct direction, unplug the fan and place it into the opening of the wooden box.
1. The fan should blow INTO the box.
Using the aluminum tape, attach the fan to the wooden box and seal all gaps around the fan to make it as air tight as possible.

Step 4: Putting It All Together

Now we are going to place it in the fireplace and put it all together.

Take the flexible pipe and place it in the fireplace in a C shape. The path of of the pipe should go underneath or onto the wood grate. I place the pipe underneath the wood grate so the red hot embers fall onto the pipe.

On one side of the pipe, place the wooden box and slide the pipe into the hole in the back of the box.

Attached the pipe to the wooden box using the aluminum tape and try your best to make as airtight of a seal as possible. At this time, also cover any more exposed wood with aluminum tape. This will help the box reflect the heat of the fire.

Step 5: Heat the House!

Now Spark up a fire, give it 10-30 minutes to get nice and hot, then plug the fan in. You will instantly feel the hot air blowing out the far end of the pipe.

If there is not enough air flow, you may need a stronger fan.