New Vermont Castings Defiant Stove Question

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sgoetz

New Member
Mar 2, 2021
2
Jamestown, OH
Hello! I'm new to the forum so thank you in advance for your advise!! We are in the early stages of installing a Vermont Castings Defiant wood stove in our log cabin home. It will be a rear vent, going straight out the wall and up the gable end of our home, 30 degree turn out and then back to clear the 2' soffit, and up above the roofline the required distance to get a proper draft (approx. 24' of vertical pipe...I think!). We have been quoted by two separate companies, two separate sized pipes (6" and 8"). From my research, it appears that the 8" was predominately used for when you wanted to leave your doors open and get the "fireplace" look and not get smoke into the room. Obviously the cost of the 8" pipe is considerably more than the 6", but I don't want to put in too small of a pipe for my application.
Anyone have any experience with these and how well they draft with 6" vs. 8"? Also, what brand of pipe do you recommend. The gentleman that quoted me the 8" (and he's been in the business for over 40 years.) recommended Ventis brand. Not sure the brand of the 6".
Thank you again,
Steve
 

RandyBoBandy

Minister of Fire
Feb 25, 2015
1,269
Whitmore lake, MI
Hello! I'm new to the forum so thank you in advance for your advise!! We are in the early stages of installing a Vermont Castings Defiant wood stove in our log cabin home. It will be a rear vent, going straight out the wall and up the gable end of our home, 30 degree turn out and then back to clear the 2' soffit, and up above the roofline the required distance to get a proper draft (approx. 24' of vertical pipe...I think!). We have been quoted by two separate companies, two separate sized pipes (6" and 8"). From my research, it appears that the 8" was predominately used for when you wanted to leave your doors open and get the "fireplace" look and not get smoke into the room. Obviously the cost of the 8" pipe is considerably more than the 6", but I don't want to put in too small of a pipe for my application.
Anyone have any experience with these and how well they draft with 6" vs. 8"? Also, what brand of pipe do you recommend. The gentleman that quoted me the 8" (and he's been in the business for over 40 years.) recommended Ventis brand. Not sure the brand of the 6".
Thank you again,
Steve
I have an older VC Encore and switched from an 8” to a 6” flue in preparation for a new stove somewhere down the line. I lost a noticeable amount of draft when I did this. I don’t burn with the doors open anyhow so it didn’t bother me much. However, at 24’ I don’t think you will have any drafting issues either way. Just keep in mind, there are not many modern stoves running an 8” flue. So if you ever decide to change stoves down the line you may have to change the flue out as well or choose from a very limited selection of 8” exhausted stoves. Ventis is used by many here so no worries on the brand.
 
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Diabel

Minister of Fire
Jan 11, 2008
3,379
Ottawa, ON
24-25’ of excel 6” pipe here. I might get a tiny bit of smoke spillage in the fall/spring (shoulder season), if I open the lid too fast. Excel makes an excellent product. Good points mentioned above.
 
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peakbagger

Minister of Fire
Jul 11, 2008
6,616
Northern NH
Hello! I'm new to the forum so thank you in advance for your advise!! We are in the early stages of installing a Vermont Castings Defiant wood stove in our log cabin home.
I suggest that you give a bit more info. Is this a brand new out of the box VC Defiant (if they still sell one) or is new to you used stove. Various iterations of the Defiant go back to the 1970s and a original design Defiant is going to have far different requirements and response to stack draft than a newer design.

In my experience the original Defiant designs were air hogs and needed a good draft to be able to transition to bypass mode. Many folks tried to connect them with 6" pipes and the results were spotty at best but frequently it was a 6" tied into an old chimney so the draft was marginal to begin with. The original Defiant was designed by folks who effectively lived in a barn heated with a barrel stove. No doubt air infiltration was a significant issue and their initial popularity was built upon installations on drafty old Vermont homes. In many cases when they were installed in newer tighter homes, they were vastly oversized and VC ended up coming out with two smaller units. In more than a few cases, Defiant's got traded in towards the smaller models when the recall for the cracked fireback rolled out.

If you have a newer, tighter home, the chimney has to work harder to develop adequate draft especially when cold. Given that your chimney is going to be exterior with a couple of offsets, that is less than an optimal chimney. My guess is that it will be an annoyance to get an initial fire going from cold during shoulder seasons. That annoyance will vary, you may need prewarm the stack with propane torch, crumpled up newspaper or some other way of getting a draft going. You may need to open a window. You may not be able to have appliances that exhaust air to the outdoors running. Then again you may not have an issue as site specific terrain features can sometimes help or hurt draft significantly .

Once you get the fire going with good dry wood, I expect the stove will be fine with a 6". Someone who heats 24/7 always has a warm stack so cold starts are not an issue. Weekend burners on the other hand have a cold stack every weekend so they are more likely to see the effects of marginal stack configuration. I stress the good dry wood as new burners rarely have it and water vapor going along for the ride up the stack is eating up volume with potential adverse effects on stack draft.
 
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sgoetz

New Member
Mar 2, 2021
2
Jamestown, OH
I suggest that you give a bit more info. Is this a brand new out of the box VC Defiant (if they still sell one) or is new to you used stove. Various iterations of the Defiant go back to the 1970s and a original design Defiant is going to have far different requirements and response to stack draft than a newer design.

In my experience the original Defiant designs were air hogs and needed a good draft to be able to transition to bypass mode. Many folks tried to connect them with 6" pipes and the results were spotty at best but frequently it was a 6" tied into an old chimney so the draft was marginal to begin with. The original Defiant was designed by folks who effectively lived in a barn heated with a barrel stove. No doubt air infiltration was a significant issue and their initial popularity was built upon installations on drafty old Vermont homes. In many cases when they were installed in newer tighter homes, they were vastly oversized and VC ended up coming out with two smaller units. In more than a few cases, Defiant's got traded in towards the smaller models when the recall for the cracked fireback rolled out.

If you have a newer, tighter home, the chimney has to work harder to develop adequate draft especially when cold. Given that your chimney is going to be exterior with a couple of offsets, that is less than an optimal chimney. My guess is that it will be an annoyance to get an initial fire going from cold during shoulder seasons. That annoyance will vary, you may need prewarm the stack with propane torch, crumpled up newspaper or some other way of getting a draft going. You may need to open a window. You may not be able to have appliances that exhaust air to the outdoors running. Then again you may not have an issue as site specific terrain features can sometimes help or hurt draft significantly .

Once you get the fire going with good dry wood, I expect the stove will be fine with a 6". Someone who heats 24/7 always has a warm stack so cold starts are not an issue. Weekend burners on the other hand have a cold stack every weekend so they are more likely to see the effects of marginal stack configuration. I stress the good dry wood as new burners rarely have it and water vapor going along for the ride up the stack is eating up volume with potential adverse effects on stack draft.

Thank you for the detailed information! I appreciate it! This is indeed a brand new unit-never previously been installed. Sounds like I need to continue my research, but 6" should work okay for my application, although not 100% ideal.