My outside hot air furnace project

I had this Fawcette hot air wood furnace given to me last summer, I don't realy have room in my garage for it so I decided to make due, and put it outside.

The silver stuff is called Reflectex, it has a class 1-A fire rating so I figured it would be a good barrier to prevent thermal transfer from the siding to the furnace.
First thing I did was to build and insulated base, 2" high R sheathing sandwich'ed betweeen 2 layers of 5/8 plywood, covered by a piece of dura-rok. Keep in mind that most of the stuff I used I had lying around except the steel studs and the reflectex and stove pipe.



my brother had just taken down a tripple wall chimney, 10" inside and 15" outsied, I made some pieces to cover the ends and filled in between with vermiculite for insulation, these are my hot/cold air lines to the garage.


my brother also had this piece of ductwork,

I've had this blower for years, not knowing what I needed it for..lol

after I framed it with 3 5/8" steel studs, I insulated it with R13 fiberglass insulation, then another layer of the reflectex.


It has a 7" stack, I put a 10" over it and filled with vermiculite, trying to keep the chimney warm, the top part is reduced to 8" over the 7", air insulated.
I am using it now, it works great after installing a new fan limit switch.
I have a couple of finishing touches to do , I will post a few more pics as soon as I get her finished up.

Neat project, it will be interesting to see how it works over the winter. If you have more pics post them up we like pics here lots of pics:hmm3grin2orange:


Beefie

nice! thanks for sharing, look forward to seeing it work!

That looks really cool, should work nice. Good job.

TreeCo said:

I love your enthusiasm but I've got a one word solution for heating with wood around here: Jotul.

No wires...no fans...no ducts...higher efficiency......no heat lost to the outdoors......great fire view.....3 days fuel supply sitting on the hearth...etc.

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Sooooo. Is this a stove. I can load my furnace and not worry about it for 12 hrs. House is still 76 deg. This is on a 3000 sq ft house. How many times would u have to load a jotul?

watch for embers from the chimni landing on the shigle roof?

do i have this right? looks like your using thin ducting for a chimney pipe but using the triple wall for your ductwork ? sounds kind of backwards

flotek said:

do i have this right? looks like your using thin ducting for a chimney pipe but using the triple wall for your ductwork ? sounds kind of backwards

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the chimney pipe is 7" heavy stove pipe, with a 10" stove pipe over it and vermiculite in between. My thought was to keep the smoke warm to the top to avoid any creosote. If I have to replace the pipe in a year or so it's no big deal, I may stumble across some metal-bestos pipe.
As far as embers on the shingle roof, It has crossed my mind, the furnace has a huge heat chamber that the smoke goes through before going out the chimney so the risk is minimal and, the whole thing is actualy big for my little garage so I have only been putting small amounts of seasoned hardwood in it at a time, maybe 2 sticks, I've been using it since last Sunday. I only light it when I'm going to be in there, I never have it going when I'm done unless it's just a few coals. So far it works awesome!!
I will post up some more pics this weekend, been swamped with work so I haven't put the finishing touches on it yet.

As far as using a jotul, I have NO room in the garage! Or do I want the sparks, i weld and paint and fab parts for my trucks, jeep or buggy. I need all the room I can get.

Here's a link to my latest welding project.
http://www.rok-freekz.com/forums/viewtopic.php?f=14&t=1996

TreeCo said:

I love your enthusiasm but I've got a one word solution for heating with wood around here: Jotul.

No wires...no fans...no ducts...higher efficiency......no heat lost to the outdoors......great fire view.....3 days fuel supply sitting on the hearth...etc.

Click to expand...

where I live my insurance co made me remove my wood stove in the garage (they said you cannot have a wood fired heater anywhere fuel may be stored) I wonder if this would be ok?

scotvl said:

where I live my insurance co made me remove my wood stove in the garage (they said you cannot have a wood fired heater anywhere fuel may be stored) I wonder if this would be ok?

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It is not where I live. No property/fire/liability insurance on home made or non-UL/etc. heating devices.

No (inexpensive)insurance on out buildings with wood burners installed in them. Specific policy addition with limitations for residential applications. Do not know about farms/business.

Most folks that installed the out door wood boilers that I have talked to did not even ask their insurance company about coverage. When I asked the answer was "NO" or "Yes, but ..." which equaled more $$$.

well it was finally cold enough here (low 20's) yesterday to see how the unit performs, all I can say is AWESOME! :hmm3grin2orange:

I have a couple of pieces of siding to put on and I will get some more pics up.

Very nice . I like the whole idea . No water to worry about. I had a stove in my shop and always thinking about those fumes exploding.

More pics as promised, I have been using this all week and it's only made it into the 20's and I'm quite pleased. My garage isn't that big but I do have a makeshift addition on the OH door end, I'll try to remember to take a pic of that, it's like the bonnet on a babies stroller, it lifts up and down so I can drive my truck part way in to work on it. It's made out of reinforced 6 mil poly.

dave_dj1 said:

More pics as promised, I have been using this all week and it's only made it into the 20's and I'm quite pleased. My garage isn't that big but I do have a makeshift addition on the OH door end, I'll try to remember to take a pic of that, it's like the bonnet on a babies stroller, it lifts up and down so I can drive my truck part way in to work on it. It's made out of reinforced 6 mil poly.

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wow you did a really nice job on that. rep comming your way

Nice job enjoyed reading it.

Thank you all for the props!
My only concern now is finding enough firewood this time of year to keep it going. I do have a friend that has a log yard a couple of miles away and he was kind enough to fill my truck with butts a week or so ago. I have just splitting it up by hand as needed. I borrowed a splitter from my brother yesterday but ended up throwing my back out trying to start the darn thing (it was left with an empty tank of fuel). So until my back heals up, I won't be burning the furnace for a while.

I really like the job you did....very nice work......you should be proud !!!!!!!!


Henry ans Wanda

Well after aprox. 3 months of intermittant use, I am here to tell you I couldn't be more pleased with this unit! I only burn it when I have a project going on in the garage (which has been often this winter). I have kept it going for up to 3-4 days at a time and it works great! I haven't had to make a single adjustment or alteration on the unit. I have had to learn to adjust the amount of wood I chuck in it, I have to keep a close eye on the outside temps. If it warms up too much and I have a good amount of wood in it, it get's too hot in the garage and I have to open a window...LOL
My buddy has been keeping me supplied with wood, I have been busy working it up and now I need a larger saw!
Happy burning