Don't know if this is the best section for this but most other places on the forum are either less relevant, or devoid of activity. Basically I'm looking into getting a wood burning stove to do the majority of the winter heating, running it on scrap / free wood as much as possible. I see them with nice fat ratings like 7/9/12 kw which from my experience with boilers / electric heating is far from an insignificant amount of heat, but I've got a couple of questions I want resolving. 1- How much of this "12 kw" is lost up the chimney as opposed to radiated into the room? 2- How far does the heat in the room get (i.e. is radiated or convected away) as i want a warm house / room, not a warm fireplace? 3- How much heat do you get from warm chimney breasts in the rooms above, assuming the heater is burning almost constantly? 4- How much wood do these things get through, as there's not much point in having one if its going to get through a quarter ton of wood every day, and with the geometry of the house we may be better off with 2 smaller ones.
I cant answer all your questions. All I know is we had a wood burning stove when I lived for a year in Reno. During the winter, we used this stove and all I burned in it was wood from pallets that I got for free. We had a 3 bedroom house approximately 1700 square feet. Load up the stove before going to bed and it would keep the entire house toasty warm all night. I was so impressed with that wood stove that I would recommend a stove to anyone in a cold climate.
I thought that you could modify it so that the soot is filtered out and the heat could be recirculated
Or better still, run the exhaust thru a washer and capture the browns gas to fuel a small internal combustion engine and generate a lil' more "free energy". Grab the wood tar while your at it, even if ya' dont need it, it's still more environmentally friendly than letting it up into the air you breathe. And wood tar stores well / could probably find a market for it if you look.
What is the effiency of the stove? That will tell you how much goes up the chimney. All new stove brochures list the efficiency, so if it is 12kW with a 82% rating it would use 9.84kW to heat the house and the remainder goes up the pipe. They also have a sq footage that the stove will heat and getting one that is rated larger than your house is not a good idea. If you do this you need to turn the stove down too much causing the stove to be less efficient and therefore you use more wood. Wood stoves are very good these days. They have catalists so that the unburned gasses get burned in a secondary stage before they get to the chimney. This has two purposes, one is to raise efficiency, the other is to reduce pollution. The less pollution the less blue smoke you see and the cleaner you chimney stays. How it heats your house has more to do with airflow from the room the stove is in to the far areas of the house. Well built houses have several things that help with this aspect, good insullation is number one, cold air returns fom all rooms is another. It does help a little to try to put the stove close to the middle of the house if it has no cold air returns. As for how much wood you burn, number one factor is insulation and cold air leaks from outside the same as with all heating sources. I had a house that was 1600 sq foot, well insulated (6" in the walls, 24" in the attic) and vapour barrier, good air flow between rooms, stove close to the middle of the house, with a air hood over the stove with a fan to blow into the bedrooms (which I rarely used because it wasn't needed) and burned about 2-3 cords of dry hardwood a year. This was my main heat all year. If I went out of town for a weekend, I would turn on the electric heat to keep the house at 50F. I would fill it before bed and then again in the morning then around supper time, except Friday night. This was to let it go out so I cold clean the ashes Saturday afternoon. Most new stoves can clean the ashes with it burning but this was one of the early catalist stoves that couldn't. This is in a cold area where it usually gets to -35 or -40F in January. If it got to hot in the house I would open a window for a while.
