Author Topic: need some advise on insulated chimneys for a woodstove.  (Read 2186 times)

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need some advise on insulated chimneys for a woodstove.
« on: August 30, 2006, 03:48:04 PM »
Well, I have a lot of hardwood , nice and dry and cut up. I hate to think what it cost as lumber-but now it is scrap. So I want to install a woodstove. Heated with one for years, got tired of the mess and did not put one in the new house. But it is getting expensive to fill the oil tank. And an alternate heat source would (wood?) be nice.
 So- I need to put in a double wal linsulated chimney, and have a couple of questions. This chimney has to go from the ceiling of the first floor, thru the second floor, thru a tall attic and out.
  #1- is there a definite advantage or dis- advantage to going up  thru the house, instead of out the side wall and up? The length will be the same. My take was that as it is a very long way up (9/12 pitcj roof), I might be better off for cleaning purposes  to go out the side wall and clean from the bottom? And the pipe would be visible for inspection. And I think I would need less for various thru floor brackets, shields, etc. On the other hand, it will be more susceptable to weather and will not look as tidy. Comments?

  #2 Are the different brands of pipe ( metalbestos, selkirk, etc) more or less the same quality?

   #3 T have a quote in hand for $1461 for materials plus $450 to install. This is five 48" pipe sections and all the supports, brackets, flashings etc to install. Represents about a 20 % increase over a year ago from the same people. At this level I am thinking of doing it myself. Comments?
  Thanks!

280plus

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need some advise on insulated chimneys for a woodstove.
« Reply #1 on: August 30, 2006, 04:23:03 PM »
I don't normally do chimneys and even less so for wood stoves. I don't know of any advantages between in over out other than what you have already mentioned. Maybe someone else does.

I'm only familiar with Metalbestos, it is a good product but expensive and those 48" sections may weigh a few pounds so putting them together 20 ft in the air might be a little tricky if you haven't worked with it before. You'll most likely need help.

$2,000 installed doesn't sound that unreasonable to me but you can always shop around. At best you'll save a couple hundred bucks if your lucky.
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Trisha

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need some advise on insulated chimneys for a woodstove.
« Reply #2 on: August 30, 2006, 05:28:06 PM »
Running the flue inside is a good way to gather the heat - and has the possibility (as in any combustibles flue/vent) of monoxide leaks, but one would likely keep an eye out for just that (and perchance keep the flue in better maintenance than were it 'out of sight, out of mind').

I suggest looking the different materials/systems up to see if there is any difference in certification levels (are both certified for commercial installations, for example).  

It's a significant DIY job.  Only you really know if it's in your capacity/skillset/timeframe.  Roof pitch, roofing material and your local fire code would be considerations, sure.
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Gewehr98

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need some advise on insulated chimneys for a woodstove.
« Reply #3 on: August 30, 2006, 05:49:34 PM »
My parents did the forced draft wood stove thing for about 10 years, until their source of cheap labor disappeared (went off to college).  Then they had no fun moving all the split and dried wood, so they went the natural gas route.

My hometown in Wisconsin has a volunteer fire department, and my Dad was a volunteer firefighter.  Almost every night during the winter he'd either have to respond to a call, or listen on the scanner while another chimney fire lit up in town.  Luckily, it was never our house.

We had an external brick chimney, and he was quite paranoid about chimney fires.  So Dad had a stainless steel liner installed, and had vermiculite poured between that liner and the brick chimney to insulate it.  The stainless chimney insert kept heat pretty well, but he would still run a chimney sweep brush into it on a regular basis.  (Think big lead weight attached to a steel bristle brush, operated from the ground by a boat winch capstan feeding steel cable through a cable guide centered over the top of the chimney)  So he'd keep that stainless chimney liner fairly clean, but he wasn't happy with just that.

He'd take the access cover out of the bottom of the chimney every now and then, stuff newspapers in there, and light them off.  This caused a chimney fire to start, and as the draft effect pulled the flames up the chimney, any residual creosote left after cleaning would light off.  It sounded like a jet engine when the fire was at full draft, but because he had cleaned it prior, the fire never got to the stage where it would cause problems.  I envisioned the lead weight on the chimney cleaner melting, but the temperatures never got to that point.  


Now the natural gas furnace they have installed uses a plain PVC pipe that sticks straight out horizontally from the foundation of the house, emitting steam and not much else.  The chimney and liner are still attached to the house, but serve no purpose other than aesthetics.

I believe the stainless liner and vermiculite probably saved Dad a lot of grief.  But I also believe his cleaning procedures and occasional small-scale chimney fires did a lot to mitigate later problems, too.
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publius

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need some advise on insulated chimneys for a woodstove.
« Reply #4 on: August 30, 2006, 06:14:18 PM »
Well, when my brother's wood stove caused a rather significant chimney fire, I was glad it was run outside the house. He should probably have taken a few lessons from Gewehr98's dad.

Leatherneck

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need some advise on insulated chimneys for a woodstove.
« Reply #5 on: August 31, 2006, 03:48:54 AM »
I've installed a couple in both workshops I built. Outside pipes are exposed to cold air, and draw off heat that you otherwise would gain the benefit of. This is less true for insulated pipes than for bare metal. The colder pipe also attracts more creosote buildup--the precursor to a chimney fire.

$2K installed doesn't seem out of line by much.

Have you considered a ventless gas log or fireplace? Depending on the cost of LPG where you are, they can be economical auxiliary heat because of their very high efficiency.

If you go the woodstove route, you'll be surprised at how fast scrap hardwood disappears. Do you have a source of free or low-cost hardwood (trees)?

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280plus

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need some advise on insulated chimneys for a woodstove.
« Reply #6 on: August 31, 2006, 04:03:04 AM »
There is also this: http://www.medfordfuel.com/Monitor_Kerosene_Heater.htm

The burner in these things is vented right out the wall and it draws air through a tube around the vent. They also can use natural gas or propane. They run on 115V. It is completely sealed from the inside air so there is NO kerosene smell. They burn kerosene with a blue flame. You can't do that with oil. You can get kerosene delivered just like oil. They are very efficient. You're probably getting 80% out of your oil heater. These deliver 93%. Just a thought.
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Guest

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need some advise on insulated chimneys for a woodstove.
« Reply #7 on: August 31, 2006, 05:54:37 AM »
Well, the main reason for a WOOD stove is I run a wood shop, right now there are a couple of cords of nice kiln-dried hardwood scraps in the shed. Since I have paid for it, it requires no cutting, splitting and is in a nice stack of cardboard boxes, it seems like a natural.
 The stove is going to be an accessory unit- we have a radiant floor setup with an oil fired boiler for the main source.

280plus

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need some advise on insulated chimneys for a woodstove.
« Reply #8 on: August 31, 2006, 09:49:08 AM »
Cool, I thought you'd be running out of wood quick but it looks like you'll have a good supply for a long time. Wink
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cassandra and sara's daddy

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need some advise on insulated chimneys for a woodstove.
« Reply #9 on: September 01, 2006, 10:04:43 AM »
i got two external ones here paid 300 for both used  put em in my self. got first one by luck  second one off craigslist.  both from folks who went with gas ventfree and wannted the chimneys gone. its nice to clean em outside  i do it every year outa paranoia  i have 2 catalytic stoves that burn very clean