Outdoor Wood Burning Boiler Construction

How to build your own outside wood burning stove

Did you always want to know how to build a clean burning outdoor boiler or furnace? Or is something you've thought up recently due to a huge fuel or electric bill just received? Or is your home ALWAYS cold?

Do you want to know how to go about building an outside heating stove for your house?

It doesn't matter why; we have the answer!

You can certainly build a clean burning outside wood burning furnace, given access to the right materials and sufficient welding skills. Remember that welding such thick materials is quite different from welding 1/8" steel because proper penetration is paramount to your success.

outdoor boiler firebox

A round firebox or cylinder is definitely the way to go. Getting a tube or cylinder already welded and x-rayed gets you one step closer to success. It certainly takes a LOT less welding than putting a square box together; taking 12 welds to do so! Remember that welds are usually the place where leaks start and flat slabs of steel are nowhere near as strong as a cylinder; bending, flexing and warping from the intense heat.

Make sure that the end plates are as thick as the firebox!

outdoor wood boiler ash repctacle

You will need to build something like this; a way for the air to blow into the firebox. This is the best way, with the air blowing up through the grates, into the fire from the bottom, just like a blacksmith's forge.

You will need heavy duty grates. These are made with 3/4" bar stock.

Before you go any further, start figuring the cost of your materials. Steel is expensive and can you even find cylinder that is 3/8" thick or 1/2" thick, like our optional firebox? Look for drill casing!

You need the end plates for the firebox - two sheets approx. 3' x 3' for a 36: round firebox.

water jacket outdoor wood boiler plans

You will also need the water jacket (box) - 6 sheets at least 4' x 5'.

You will need about a 5 foot chimney pipe. We recommend 1/4" thick steel.

Weld the chimney into the firebox.

Don't forget an access cover for the hot water coil, as shown above, which will save you $35.00 to $65.00 a month in electric bills all by itself!

If you are putting on siding, such as steel building metal, you will need a frame around it (see picture) and framing for the roof.

outdoor wood boiler door plans

Remember you will need to build a door too; preferably with an air gap to provide the insulation value; similar to air bubble type insulation. Attach the plate with 4 small pieces of metal so that there is very little heat transfer from the plate to the outside metal. Water filled door are a farce because you end up with over 60" of metal or more, surrounding the water filled air which just leads to a lot of heat transfer which the water does very little to abate. Adding to that, the water is not moving inside the door even if you have hoses attached and that will allow particles to settle; and think about the lack of rust protection in that area!

build a clean burning outdoor furnace water supply

You will also need plumbing to fill the furnace as well.

NOW, consider this. You can purchase a HyproTherm 185 for only $4487 without the siding, insulation, pump, fan, hot water coil and thermostat.

We also occasionally rebuild these exact boilers and they are $1500 less than a new one at $3877. Every once in a while, a customer will trade one in and we go through them top to bottom and inside out as explained on our Used Boiler Page.

I don't believe you can build the same furnace, with the 1/2" thick firebox for under $3000.

You can put any kind of siding on it that you want or we can provide 21 different colors, and 8,000 color combinations, for you. Of course you will need the pump, fan, hot water coil and thermostat or you can get your own locally.

build a clean burning outdoor boiler cutaway picture