I'm not sure if this discussion might be more appropriate in the regular wood stove section, but I bought a 2 level 1970 rancher home, approximately 3,000 square feet with a home built forced air wood furnace. It is about the same age as the house, built by the previous owner. It is in some ways a marvel and I've been impressed with a lot about it but it has room for improvement. There are three things, specifically.
First, it is inefficient. Or seems like it anyway. It consumes 10 cord of tamarack every year, rain or shine. Granted, the fire burns 24-7 from the end of October through the first of April and it is a fairly large space to heat with some insulation inefficiencies. In addition, the firebox is completely open, so a huge portion of the heat generated by the fire goes up the chimney and isn't able to warm the circulated air.
Second, the draft is incredible on this machine--unless you open the door to add wood. When you do that, the entire garage and subsequently the house fills with smoke. I have dealt with this by adding a wheelbarrow of wood morning and night with all the doors open in the garage so that the wind blows the smoke away. But I lose a lot of heat, obviously and smoke still gets in the house.
Third and most important, I'm concerned about the safety of the thing. When it is cold I put a lot of wood in there and flirt with very high flue temps in order to generate enough heat to keep the house warm. It will make enough heat to keep the house warm in sub-zero temps, but I have to put a lot of wood in it and allow enough fresh air to create a substantial fire--much of which goes out the chimney.
I had considered going to an automated wood furnace or even an outdoor unit but I'm cheap, stubborn and like experimenting so I thought I could try to modify the firebox by adding a baffle system which might help solve all three problems. The firebox is made of an old pressure tank of some kind and is at least 3/16" thick. It is 40 inches deep with a 29 inch diameter. The air control is a 6" square door in the front. The outlet pipe is 6" round, about 6 inches from the back of the tank which goes up and immediately 90 degrees into the masonry chimney with a 6x8 clay flue which is about 25 feet tall.
I'm thinking about cutting some 1/4" sheet to fit and make a shelf about two inches below the outlet pipe and force the gases to travel to the front of the box before going back to the outlet. The problem is I'm sure that will make the smoke problem even worse, but it might be worth it to achieve greater efficiency and safety. Maybe both a baffle and smoke curtain?
I have attached a crude sideview diagram of the furnace. If anyone has suggestions or places to look for more information, I would love to hear about it. Thank you!
First, it is inefficient. Or seems like it anyway. It consumes 10 cord of tamarack every year, rain or shine. Granted, the fire burns 24-7 from the end of October through the first of April and it is a fairly large space to heat with some insulation inefficiencies. In addition, the firebox is completely open, so a huge portion of the heat generated by the fire goes up the chimney and isn't able to warm the circulated air.
Second, the draft is incredible on this machine--unless you open the door to add wood. When you do that, the entire garage and subsequently the house fills with smoke. I have dealt with this by adding a wheelbarrow of wood morning and night with all the doors open in the garage so that the wind blows the smoke away. But I lose a lot of heat, obviously and smoke still gets in the house.
Third and most important, I'm concerned about the safety of the thing. When it is cold I put a lot of wood in there and flirt with very high flue temps in order to generate enough heat to keep the house warm. It will make enough heat to keep the house warm in sub-zero temps, but I have to put a lot of wood in it and allow enough fresh air to create a substantial fire--much of which goes out the chimney.
I had considered going to an automated wood furnace or even an outdoor unit but I'm cheap, stubborn and like experimenting so I thought I could try to modify the firebox by adding a baffle system which might help solve all three problems. The firebox is made of an old pressure tank of some kind and is at least 3/16" thick. It is 40 inches deep with a 29 inch diameter. The air control is a 6" square door in the front. The outlet pipe is 6" round, about 6 inches from the back of the tank which goes up and immediately 90 degrees into the masonry chimney with a 6x8 clay flue which is about 25 feet tall.
I'm thinking about cutting some 1/4" sheet to fit and make a shelf about two inches below the outlet pipe and force the gases to travel to the front of the box before going back to the outlet. The problem is I'm sure that will make the smoke problem even worse, but it might be worth it to achieve greater efficiency and safety. Maybe both a baffle and smoke curtain?
I have attached a crude sideview diagram of the furnace. If anyone has suggestions or places to look for more information, I would love to hear about it. Thank you!
