Alex how hot is the air blowing out of the registers?
Also, how many CFM are you pushing?
Do you have a picture of your setup?
I have a hand fired stove tied into my main ductwork. My setup isn’t the best, but it works. Right now I’m blowing 125 degree air about 3-4 feet from my fans. Its 70 inside in my main room and most living space, in about 1500-1600 sq ft (built in 1950, new windows), about 10 degrees outside. I’m just pushing the air with 2 - 8inch in-line duct fans off the stove (420 cfm x 2, 840 total cfm). I have a long run in one room in my 2nd floor, I have one 6 inch duct fan on a 110 inline thermostat (aka baseboard heater thermostat).
When my gas furnace runs its about 130 degree air, but much more cfm, maybe 1000 or 1500.. it’s a 74,000 output 92 efficient model.
I haven't burnt any natural gas during this cold spell… infact my gas furnace doesn’t run and my bills are just like my summer bills around $30/mo. I was down to 66 degrees for a short time when it was -1 degrees out with 20 mph winds (Monday morning), but it was back up to 68 and 70 after some hard burning (with 130-140 degree air) and fresh coal.
Its very doable, don’t let anyone tell you its not.
Here is a pic of my setup. http://nepacrossroads.com/files/2006_12 ... 00_100.jpg
I've adjusted a little since then with a smaller take off on my hot water heater to get a more direct flow into the plenum, but same idea.