I have an opportunity to put a huge old hot air blower type wood furnace outside my home and at a distance that’s safe for my home, from the possibility of fire from the (insulated) flue, and run an insulated air duct – or possibly two; one for return air, one for heat, into my home to heat it with, as this spring, we had a tornado that blew down 3,000 local trees, so wood is easy to find and much cheaper than natural gas, propane or electric as a furnace heating fuel. I’ve searched high and low online for info to convert, or rather to insulate the furnace with fire-proof or high heat insulation and cover the furnace with a sheet metal shell, (so as to not make a huge building to put it in, but more or less, a self-contained unit), to protect it from the elements of winter and make it operate more efficiently, but have found nothing but info and ads for ‘outside wood boilers’. I was going to put it in my 10 x 10 metal garden building storage shed, but the storm blew it away. Now I’m faced with 48 – 52 degrees F indoor temperatures while running an oil-radiator electric heater in one room, an inadequate income to buy a new wood stove that’s EPA Approved and UL Listed to have professionally installed inside my home, and when I run my gas furnace, it sucks outside air into and through the house (I imagine, for combustion), in spite of much insulating, caulking and sealing I’ve done, making the house drafty and cold, and in spite of putting out warm air (kind of defeating the purpose of having it on in the first place). … However tonight I learned that by creating a suitable sized outside air intake to the combustion area of my gas furnace, will reduce or eliminate it sucking cold air from outside into my home, and in the process, burn less fuel, and heat the house more efficiently. So anyway, can someone please make a suggestion what should be used for high-heat insulation, to cover my furnace with, i.e., especially, the air jacket, (which is a heavy 1/4″ plate steel box that’s welded to the fire box surrounding it), and operates cooler than the fire box temperature?
you have to have mighty good insulation on that ductwork. your getting this confused with outside woodburning boilers. they heat up a heat transfer fluid, and then that gets pumped through supply and return lines to a furnace inside the house. the furnace is normal except it doesn’t require propane or a heating coil. your project sounds like something a bored hvac tech would try for they’re workshop. to complicated. you would be better off building a small addition to your house to install it in if you don’t have the room. i just can’t think of a suitable enclosure for the furnace, not to mention how you would install the supply and return. for some reason a very small shed attached to your home comes to mind as a suitable place to install the furnace. anyway what you are thinking of doing would violate a ton of fire and building codes. don’t try it and buy a bunch of space heaters.