My outside hot air furnace project

[Blazin]

Good deal! Nothin better than a warm garage to work in!

 

[Putter]

Very nice and tidy. You did a good job. Any details where you mounted the blower and pictures of the heat exchanger and firebox would be interesting.

 

[dave_dj1]

Very nice and tidy. You did a good job. Any details where you mounted the blower and pictures of the heat exchanger and firebox would be interesting.

Thanks
In the first and third pic on this page (page 2) you will see a little brown section of siding, the cold air is on the bottom, blower sits inside the bottom, if you look at the first set of pics on page 1, the base has a spot sticking out for the blower to sit. The wood furnace itself I did not build, it is a Fawcette, still made in Canada. The heat exchanger is on top of the firebox and is round, as well as the firebox being round. There is NO water running through this unit, strictly hot air.
I am contemplating finding antother similar unit and building another one for my house. I think it would pay to buy a brand new one and start from there. I am scouring CL in hopes of finding a suitable unit for the house. If I can't find another one that I like I may move this one to the house for next winter and still keep searching for another similar unit.

 

[Dustinthewind55]

Thanks
In the first and third pic on this page (page 2) you will see a little brown section of siding, the cold air is on the bottom, blower sits inside the bottom, if you look at the first set of pics on page 1, the base has a spot sticking out for the blower to sit. The wood furnace itself I did not build, it is a Fawcette, still made in Canada. The heat exchanger is on top of the firebox and is round, as well as the firebox being round. There is NO water running through this unit, strictly hot air.
I am contemplating finding antother similar unit and building another one for my house. I think it would pay to buy a brand new one and start from there. I am scouring CL in hopes of finding a suitable unit for the house. If I can't find another one that I like I may move this one to the house for next winter and still keep searching for another similar unit.

I realize this is an old thread but I am in the process of doing this exact same thing and have ran into one roadblock after another. This thread has helped me a bunch but there are still things I'm not quite sure about and would love to ask someone that has been there done that. My big question right now is...are you basically using the building that you built around the furnace as a second jacket? And what I mean is the building sealed tight enough that you actually have your heat duct coming out of the building as opposed to out of the top of the furnace? Or is it hooked up as it normally would be if it were inside the home and if so does the heat inside the building itself cause an issue? I hope I am making sense.

 

[Marshy]

I realize this is an old thread but I am in the process of doing this exact same thing and have ran into one roadblock after another. This thread has helped me a bunch but there are still things I'm not quite sure about and would love to ask someone that has been there done that. My big question right now is...are you basically using the building that you built around the furnace as a second jacket? And what I mean is the building sealed tight enough that you actually have your heat duct coming out of the building as opposed to out of the top of the furnace? Or is it hooked up as it normally would be if it were inside the home and if so does the heat inside the building itself cause an issue? I hope I am making sense.

It appears to me that he used the normal ducting from the furnace unit an only added the structure around it to protect it from the elements and provide some insulating protection from the cold. The front door as air holes down in the bottom of it for combustion air to the firebox... Just what I see, hope that helps you if he does not respond

Very nice work BTW.

 

[dave_dj1]

Kind of both, the structure is insulated and sealed too. I wrapped the furnace with a product called reflectex, it's like bubble wrap.
One thing I found is that the air travels so fast through the ductwork that in reality, you don't need any insulation. The only downside I see to no duct insulation is you would get a shot of cold air initially. I wouldn't have that problem as my blower hardly ever shuts off!
To do it over again the only thing I would really change is the top, I should have had a larger size plenum on the top, I think the close tolerance I have is why the blower runs almost constantly.
Good luck and ask away. I don't think I have any more pics but I am willing to answer any questions I can for you.
dave

 

[Dustinthewind55]

Thanks Dave and Marshy for getting back with me. I tend to over analyze things and have spent the last couple of weeks trying to figure out just what to do. I am familiar with the reflectex and will use that for sure. I also agree about the air traveling fast enough to not really cool it down a bunch in fact a guy down the road that once sold wood furnaces thought it might be more important to insulate the cold air return. We are primarily wanting it to heat a large family room so I doubt I will fire it really heavy nor expect it to hold coals for a long time. My biggest concern is the heat inside the building itself. I know there is conductive heat from the furnace jacket and with no way for it to escape I wonder about the wiring. Have you ever noticed that being a problem? I also thought today that I would build in an access door in back as well as the front in case it becomes necessary to vent the building for any reason such as a power outage. Is your blower located on back of the furnace blowing through the jacket or is it in the square box at the top of your furnace sucking air through it? I'm sure I will come up with more questions as time goes on....thanks again for your input.....Steve

 

[dave_dj1]

Dustinthewind55, if you go back and look at the 8th picture down you will see my cordless impact gun, that is where the fan sits, it blows in to the jacket and comes out the top square. No real reason for that big square box other than my brother gave it to me. The jacket is insulated, my walls are built tight to the reflectex and then wrapped with fiberglass insulation. To do it again I would make the walls about 8-10" thick for max insulation. The peak I just stuffed full, snow will sit on the roof for a while, I'm sure there is some heat loss. To me the idea is to keep as much heat in the jacket/furnace to use in the house. The only venting I have is in the bottom of the door for air intake for the fire. It's 34 out right now and 73 in here I only lit the thing at 8 last night and stoked it at around 10. I'm heating a walk out ranch which is a total of sq ft of about 1900. I do have good windows and some extra insulation in the attic and we sleep with the bedroom window open about 2:. LOL
Again, anything you want to know just ask. I'll do my best to answer.
dave