unconventional stovepipe run to save more heat?

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I'm going to be putting in a woodstove for winter heating, and I'd like to get a little more heat out of it by extending the run of uninsulated stovepipe in the room before I tie it into an existing chimney. I've seen a few photos of this idea, for example:
http://www.motherearthnews.com/library/1980_November_December/Build_Your_Own__90__Efficient___Fireplace
Aside from the odd appearance, there are obviously concerns about draft and creosote buildup. I don't think the draft would be a big problem, since the chimney tops out at my roof peak (2-story house) in a relatively windy part of the country. And it seems like much of the creosote would collect into the bottom "curve" of the run which could be removed for cleaning.
Has anyone out there experimented with this sort of idea or have thoughts on how it might work/not work?
Coyotefred
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snipped-for-privacy@gmail.com wrote:

http://www.motherearthnews.com/library/1980_November_December/Build_Your_Own__90__Efficient___Fireplace
You're looking for heat transfer. Attaching some metal fins on the straight chimney would probably do as much for the heat transfer and eliminate the obvious problems with running a chimney section upside down. I'm sure there are factory built units, or you could rig one for yourself fairly easily.
R
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snipped-for-privacy@gmail.com wrote:

http://www.motherearthnews.com/library/1980_November_December/Build_Your_Own__90__Efficient___Fireplace
If you've got a good stove and you keeping a good hot fire you shouldn't have to worry about creosote, and a long run of flue pipe or a Magic Heat is a great way to get better efficiency from your stove. Get an old Magic heat, the one with about ten tubes in it, there's a new one that has four tubes, you'd be better off with a long run of flue pipe..
Looking at the site you referred to.. I've found Mother Earth News to be something that's probably great for hippies, but the "Far Out!" factor dwindles rapidly as the temperature goes below zero.. This is classic: " According to its builders, the fireplace will when loaded with five pounds of wood and lighted give an instant dose of heat to the room through its stovepipe." No matter the efficiency, what good is five pounds of wood heat?
If you make a run of pipe down toward the floor and then back up you'll probably get a much better heat exchange.. it might be a little harder to get a good draft if the house is cold but a couple of sheets of newspaper wadded and blazed as you're starting the fire should take care of that. If you get the pipe closer to the floor (and into the colder air) it'll naturally heat the air more efficiently. The more the pipe changes direction the more heat transfer you'll get for a given length too..
John
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snipped-for-privacy@gmail.com wrote:

Draft might come from a 240 V muffin fan running on 120 V over an adjustable hole in the door. Dry creosote buildup may be unlikely in a chimney with condensation, which can add 15% to efficiency.
To cool a 6" pipe inside an 8" pipe, you might use a 10" fan in a 10" to 8" reducer below an 8" T near the point where the 6" pipe leaves the house to blow room air back towards the stove through the space between the pipes, with a CO monitor in the room.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Do you mean condensing moisture? It'd sure add to the efficiency, but what do you do with the stinky moisture.. if you leave it in the pipe and expect it to "evaporate" then the efficiency gain is lost in the latent heat (which is the gain realized by condensing the moisture in the first place).. you could have a trap for it to flow to, but then you gotta deal with it..
John

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Of course.

Let it drip into a plastic bucket.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

It'd work, and with some wood it'd certainly increase the efficiency in a dramatic fashion. I don't believe it'd be much help with well-seasoned hardwood, but with wet or oily woods (pine and walnut in particular) it might really be worth the effort.
John
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Couple of issues: 1. To have natural draft, you need temp diff for some vertical run. 2. When firebox temp below about 1000 deg F, unburnt volatiles escape, to condense in cool areas (from top, down). 3. Air drawn into device affects overall efficiency big-time, since it's heated. (So the 90% claim sets off my BS-alarm.) Not to mention biggies about Fire Marshall, insurance, etc.
To go for extreme efficiency, as others have discovered, you first need complete combustion: temp, air-fuel ratio, mixing. Insulated firebox with controlled draft help a lot. Then you can transfer heat as possible. For really extreme efficiency UMO Prof. Hill used forced draft.
Using available items, avoiding electrical requirements, I'd suggest: 1. EPA-approved non-catalyst woodstove of output and quality to suit you. 2. 6-8 feet of single-wall black smokepipe, with all sections angled up or straight up. 3. Fuel that is as dry as you can make it, fed in such a manner that it does not quench flames if possible. 4. Sacrificing efficiency on occasion by allowing extra airflow, on startup to heat flue, and on loading fuel.
Taking it a small step further, I use a few small pancake blowers to stimulate airflow over hottest part of stove, and past lowest part of pipe.
Installation should be done so as to meet all codes, obviously.
Not a conversation-piece like the one in the article, but it can be made to work very well. YMWV.
HTH, J
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I am installing a wood stove myself. Initially I thought I could just remove my natural gas stove and replace it with a wood stove. This vents into an existing brick chimney.
I learned that my homeowners insurance would not cover me for a fire if my wood stove was not installed to code, inspected and passed, and also inspected by my insurance company.
So I could lose *everything* if I just stuck a wood stove in my house!
I am going the permit route which requires all sorts of stuff, but for your specific situation, read the following which is from the Selkirk chimney manufacturer's frequently asked questions link below.
"Are there any limitations to the use of elbows?
Yes. The UL 103 Standard, our instructions, and codes prohibit any offset creating an incline greater than 30 from vertical. The use of a single 15, a pair of 15 's (to get a specific angle between 0 - 30 degrees) or a single 30 is allowed (with the same combination to return to vertical following the offset). If there is a long inclined run, (longer than 4 ft.), it needs to be supported at least every 48". Also an offset needs to be supported at the first section above the upper elbow(s) where the system returns to the vertical orientation."
http://www.selkirkinc.com/faq/index2.html#18d
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snipped-for-privacy@sme-online.com wrote:

Barry has the clue.. it takes considerable temperatures to break creosote down to where it'll burn. It's a very heavy hydrocarbon, what you see on utility poles, and it won't burn at lower temperatures. That's why the square stoves leave so much creosote in a chimney, that's why people need the insulated pipes to keep creosote accumulation down- but they send vast amounts of heat up that pipe along with the lost heat the creosote would have made had it been burned.
Burn the fuel efficiently and entirely at high temperatures in the stove, take the heat from the flue pipe.. that's what works.
John

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I'd suggest using standard double walled pipe with the shortest / most direct vertical route possible. I'm interested in finding out how they came up with 92.6% efficiency - doubtfully using any accepted UL methods.
Problems with the convoluted stove pipe will be: 1. Your building/fire inspector won't pass it 2. Your insurance wouldn't likely give you coverage for your house 3. Major creosote build up due to bad flow 4. PITA for cleaning
I'd spend my money on a good, efficient, modern stove. I've found deep ones better at burning than wide ones. Go double walled. If you want more heat then use a fan to blow air around the stove.

http://www.motherearthnews.com/library/1980_November_December/Build_Your_Own __90__Efficient___Fireplace
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http://www.motherearthnews.com/library/1980_November_December/Build_Your_Own__90__Efficient___Fireplace
Sorry I would have replied quicker but I was too busy laughing once I saw the webpage.
While something like this might be a conversation piece in Arizona, on those cooler nights.
I wouldn't suggest relying on it in Minnesota, or anywhere else north of Tennessee.
And it does CLEARLY say this is a fireplace not a woodstove, so the chimney is designed for that
First issue is creosote buildup. How are you going to know WHEN it's time to clean it ? Without pulling it apart every week. That could get very messy, and there is that "fire hazard" thing, if a chimney fire starts how are you going to put it out ?
Fireplaces and woodstoves are two different things.
In a sealed woodstove the idea is to cut the rate of combustion by holding back air that would otherwise go up the chimney. Raising the actual temperature in the firebox to allow complete combustion of the fuel.
This usually means a woodstove chimney is much cooler than a fireplace so condensation and creosote, and draft is more of an issue.
But since this is only an opinion that you can ignore.
my vote is "don't do it".
AMUN
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Some wood stoves introduce air into the flue leaving the stove to burn off creosote in a box just before the chimney. Note that creosote is a volotile that condenses out of the flue gas. If you are condensing water you will condense creosote also. Nick is correct about the efficiency increase, however there are problems with a wood burning appliance. Condensate in the flue is slightly acidic, the flue pipe should be designed to handle it. If you condense the water out of the flue, it will be too cool to establish a good draft. You will need a draft inducer. DO NOT USE a muffin fan. Tjernlund makes them for gas burners, see if they make one that would work with wood.
Your idea is interesting, but fraught with peril, as the side effects of what you propose could be dangerous. Buying a good quality air tight wood stove will increase your efficiency safely without having to jury rig a lot of questionable doodads that may not work as desired. Good luck.
Stretch
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I agree that a modern, airtight, etc. woodstove would be a nice alternative, but I don't have a couple of grand sitting around to buy one :) I'm not quite sure who some of these stove companies think their market is, but in my neck of the woods I don't know too many folks with that kind of money available. I'd like to see a few more decent quality stove options for average folks and their paychecks...
In any case, I like fin idea. This would seem to avoid all of the potential problems several folks have raised with a convoluted stovepipe run, but still allow you to get some decent heat transfer...
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Hey I hear you on the price issue. Either hurt now or hurt all the time later. If you have a cheap stove your heat goes up the chimney and you are spending your time/money loading the stove with wood.
Keep an eye out at liquidation places etc. I've seen brand new $2K stoves selling for $800.

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$1K for shipping too.

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In misc.consumers.house snipped-for-privacy@gmail.com wrote:

Have you checked out used stoves on ebay and craigslist? Used stoves are more $$ this time of year than any other, but still a lot less than new. Some of them are barely used and in excellent condition.
I personally view a high end wood stove as a long term investment. Spend $2500+- on a stove, pipe, hearth, chainsaw, and maul today to you can reduce your heating bill by $1000+- per year for the next 20 years. Also you can sell a high end stove as "decorating the living room" to a wife. :-)

A much safer idea than the crazy pipes you were considering.
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OK, Coyote, what is it you want? That's the first thing you need to figure out.
When my ex and I were in the Yukon on a mine claim, we had a very rough house and a poor stove, and nothing to insure. I'm too embarrassed to tell you how bad out heating system was. But it was cheap. And at that time, that was our priority.
Now I live in a log cabin, with nice stuff that I want insurance on. I have water only in a holding tank, so I couldn't even insure my place if I claimed fire as a heat source -- other than for emergencies. Insurance dictates that the stove be on a hearth, be a certain distance from walls, have a certain kind of chimney, etc. That's going to have to be what you ask yourself about first. Well, that and safety.
I haven't looked around at stoves for quite a while, and don't remember names of specific products, but I remember little stoves of thin metal with a lining. From Army Navy, I think. Those linings wear out, and I wouldn't trust their safety, especially if you have to keep the box real hot. Wouldn't trust anything but cast iron.
And of course, there's comfort. To me, that means the house is warm enough and the fire lasts long enough that it's not necessary to get up to tend the fire in the middle of the night. Our place has about 1000 sq ft, and is the "trapper" style -- low pitched ceiling, and open floor plan (U shaped space the guts of the house, like the bathroom, boiler, water pump, closets, etc), so the stove and a little heat powered fan are plenty for us. Part of keeping the fire going is getting a stove that's tight enough and also controllable. Once again that means a decent cast iron stove.
And decent cast iron stoves cost. But they also last. As it happens, we got ours new. Ordered it through our local wood stove store from Vermont Casting, because that's what my husband wanted. I thought it was a little frivolous, but am so glad we chose it. The store had other less expensive stoves, and also had used reconditioned stoves from trade ins.
But there are other places to look too. Try junk shops, try Tradio or your local equivalent, want ads, free ads, ask the old timers to ask other old timers. Maybe estate sales or garage sales.
I agree with Janet. A good stove, properly and legally installed is an important long term investment. The only way to go unless you REALLY have nothing to lose.
Tina
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CAN last - or you can get caught out like I was. My first cast iron stove was great, it was Scottish I think 'Esse' brand, but it was a cooker with so much hot water boiler around the firebox it never even got the kitchen warm, never mind the rest of the house. So I replaced it with a locally made one 'stainless chrome nickel cast iron specially formulated' stove - slow combustion etc... after 4 years the foundry that made it had been sold, the company who had bought them up had been sold, and I was left with a stove that had a half inch open crack all the way up and down one side that I could certainly not get parts for any more. Cast can be tricky!
I now have a new stove <sigh> and it so happens it's 1/4 inch boilerplate steel, welded. Performance is just as good as the cast stove, and while the [ceramic baffles] inside have deteriorated in two heating seasons, the steel is as good as new.
-Peter
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I have both a vermont cast iron stove and a pacific fab. steel double walled stove in our log cabin. Pacific is in the basement, vermont in the parlor.
The pacific is narrow and deep, burns all night on one load, throws tons of heat, excellent reburn action on the gases. 100% consumption of wood, burns front to back. It runs from October to April. My chimney is clean as a whistle.
The vermont is wide and narrow, looks pretty, and is a POS when it comes to heating, but looks really nice. It's also top/front load and you can make a great pot of coffee on it. I fire it up a couple times a year or during power failures in mid winter. Does a lousy job burning wood. It burns from the middle to the sides. I have to keep feeding it like a baby chick. It doesn't keep hot enough. But it looks pretty.
Previously in other houses I've had a cheap fab. steel stove and an expensive cast iron elmira stive.
So far if I'd have to do it again I'd put my money down on another pacific. No questions asked. Cheaper than the vermont/elmira and best performance so far.
says...

we
Vermont
little
expensive
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