Wood stove insert installation advice; Do I need to insulate liner? Is a reducer a bad idea?

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Do I need to insulate? Is it ok to use a reducer?

  • No need to insulate. Reducer is ok to use.

    Votes: 1 8.3%

  • No need to insulate. Reducer is a bad idea.

    Votes: 4 33.3%

  • Need to insulate. Reducer is ok to use.

    Votes: 2 16.7%

  • Need to insulate. Reducer is a bad idea

    Votes: 5 41.7%
  • Total voters
    12
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BrotherBart said:
No way to know until we know what that chimney is. Lining a chimney isn't a walk in the park. It is a dirty, dangerous job with the working on a roof factor. And you virtually always have some kinds of obstructions and offsets in the chimney.
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I called A+ Chimney Cleaners (the company who inspected my chimney), and they were able to tell me that I had a standard clay chimney. Despite my pride hurting, as well as my wallet, I think I'm going to pay them to do the work.

The best price I was able to find for the 8" x 25' liner kit and insulation was $660. A+ said they were a little low on business right now so they would do the install, with parts, for $1,250. If I was going to live here forever, or if adding a wood stove insert to the house added any resale value, paying the $600 difference for someone else to do the dirty work would be a no-brainer, but since I'm going to be heading wherever the Air Force sends me in the summer of 2017, shelling out the extra cash does hurt a bit. I'm not sure if I'll be able to recoup the expense in energy savings over the next 3 winters, and my friend is still convinced we're capable of doing the work ourselves, but the cautious side of me (a very small part of my inner being) says to pay the contractor. My concerns of doing the work myself are:

1) Accessing the top of the chimney. I've been on top of my roof, but the chimney sticks up another 8 feet. I don't exactly have easy access to scaffolding, so I'm not really sure how I would safely get up there to install the top plate. I couldn't exactly stand on the roof like this guy: (see picture)

2) Obstructions in the chimney. It seems like a 13x13 chimney is plenty of space to shove down an approximately 8.5 inch diameter tube, but I have no idea how I would deal with having to remove obstructions inside the chimney, should they exist.

Thanks everyone for the advice and expertise, and please feel free to offer more if you have it. This was my first hearth.com experience and I was very impressed with the plethora of knowledge and willingness to share. I had no idea forums could be so useful.

Damn it...even as I sit here typing this I'm thinking "what if we could just do it ourselves?" Probably always going to wonder that...
 

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Good decision. I have done them but for six hundred I would let somebody else do the next one. Everything doesn't have to do with pride or return on investment.
 
a316co2000 said:
t seems like a 13x13 chimney is plenty of space to shove down an approximately 8.5 inch diameter tube,
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It's not 13x13 inside. It's only 11x11 and the liner with 1" insulation will be around 10.5". It may be tight. (Unless I'm misunderstanding and it's actually a 16x16 clay liner which is 13.5x13.5 inside.)

There also are preinsulated liners. Insulflex comes to mind. You mentioned "like used car dealers". That's probably the right idea as far as pricing goes. Have gotten the impression that you can bargain on the price for these liners a lot of the time like with a car. It's not like buying from a dept. store.
 
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I still think an 8" liner is a bit of a white elephant....most new EPA inserts require a 6". I say go for an insulated 6" with a blockoff, save a little money, and use the current freebie insert. If it doesn't burn right...sell it on CL for more than you paid for it (free) and use the cash to buy something else on CL. IM(Humble)O an insulated 6" liner is gonna pull a lot better than a slammer in an exterior chimney, unless its 12' tall. Oh yeah, how tall is the stack?
 
Yes wood geek it may work but my thought is it will not pull as well as it should causing more buildup. and as soon as you start to get build up in that 6" you are going to have lots of problems.
 
Comes down to the operator. A bad operator could choke up an 8" liner, a good operator could keep a 6" liner clean, esp with a cat. Might just be a slight air adjustment difference between the two cases, same airflow and burn profile otherwise.

Unless you were planning on getting 1" of creosote in the liner, I don't see what the liner size would have to do with it.

Alternative scenario is OP squeezes in $$$ 8" liner, and then decides the old insert is no good (just as likely IMO as having a problem with a 6" liner), and now he is locked into finding a new unit that takes an 8" liner, pretty much blocking him from anything of a newer vintage.
 
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while I agree with you wood geek that it will come down to the operator. It will be much harder for someone to operate the stove properly with a liner that is only 3/4 the necessary size. Also if he is thinking of renting the property everything needs to be done to code and to make it as easy as possible for someone to operate. That means insulating and no down sizing.
 
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How times change....

this thread from 2007 describes a Derco cat stove as a pre-EPA unit that is best suited to being a 'boat anchor'.

https://www.hearth.com/talk/threads/modified-need-advice.11157/

In 2014 we have 3 pages of discussion on the importance of spending $1000 for an 8" insulated liner. LOL.

I'm no snob....I'm running a 35 yo pre-EPA insert with a 8" direct connect. But I wouldn't burn it 24/7, or plan on letting renters do it! _g

I still say the OP can scrap the DERCO, put in a $600 6" liner and put the $400 left over towards an EPA unit.
 
I agree with you on that point for sure wood geek. But that was not his question I answered his question as best I could. But if it were me I would get a better stove and put in a 6" insulated liner as you suggested.
 
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I am no snob either I am running a almost 40 y/o cawley lemay 600. But I would have to say it is a better stove than many of the newer ones out there. It has secondary combustion burns clean and cranks out the heat. But I do feel that a properly sized and insulated liner makes a stove much easier and safer to operate.
 
further research reveals 3 cat models from DERCO are EPA listed:

g/hr BTU/hr % Eff
x Derco, Inc./Grizzly Stoves Super Achiever FPI-2-LEX 2.4 9800-34200 72 Catalytic
x Derco, Inc./Grizzly Stoves Little Blazer FP-20 4.7 7200-28400 72 Catalytic
x Derco, Inc./Grizzly Stoves Little Blazer FP-20 4.7 7200-28400 72 Catalytic

Free EPA stove in good condition....score. Free pre-EPA requiring expensive venting....not a score.
 
Don't recall an indication of s.ft. but if it's a larger house, being locked in with an 8" liner is not really a detriment in the current market for stoves. All the larger than 3 cf ones require an 8" liner -- thinking BK King, Buck 91, 94, Kuma Sequoia, et. al. Besides he said it's a two story house, so the chimney is likely over 20' or more and with an 8" insulated liner, he should be able to use most stoves with 6" stove collars and an enlarger fitting, I would think if he decides to downsize.

I wouldn't look at the 8" insulated liner as a white elephant limiting his future options. In fact when I was planning to replace the too-small-for-me Century insert, I was disappointed that I only had a 6" liner which ruled out those larger stoves that required the 8".
 
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Wow, lots of replies to this thread, yet stopped getting e-mail notifications and wasn't aware others had posted. I wish I had seen these comments before making a decision, alas I did not.

I was able to negotiate multiple ebay sellers down to a total of $625 for an 8" 25 foot liner kit, and an insulation kit to go around it. I also got up on the roof with a friend last weekend to ensure a 25 foot liner would be long enough, and to see if there were any obstructions. It looked clear all the way to the bottom so we decided to do the job ourselves, which is when I ordered the parts. They arrived 2 days ago, so I'm hoping to install the liner this weekend (depends on my friend's availability).

As for the stove, I still have hopes that it will perform to my satisfaction. I found another forum on here posted by an owner of the exact same stove, and he was very happy with its performance, so hopefully I will be too.

The only challenge I foresee now will be getting past the damper. The narrow part of it is only 6.5 inches, so I don't know if I should try cutting it or ovalizing the liner. I'll post a separate topic on that discussion.

Thanks again everyone for the inputs and advice.
 
How much vertical from top of stove to top of liner.....sounds like 20-25'
 
Well the job is done and the stove works great, though the weather has warmed up so we only really used it to make sure it worked (so far).

We ended up ovalizing the last 2 feet of the liner and, once getting it through the damper hole, made the end round again to connect it to the stove. I decided to go with that method because after removing the damper (flapper part) it became evident I would have to remove some fire brick to avoid ovalizing the end of the liner, and I wasn't comfortable attempting that. Ovalizing it did make it a little tougher to get it shoved down the flue, but with a little brute force we made it work, and I feel good about being able to do the job ourselves.

Thanks everyone for your advice, which ultimately led to me spending an extra $250 (though it is nice knowing the job got done right). I'll post some pictures once I get the rest of the trim painted and put on the stove.
 
a316co2000 said:
Well the job is done and the stove works great, though the weather has warmed up so we only really used it to make sure it worked (so far).

We ended up ovalizing the last 2 feet of the liner and, once getting it through the damper hole, made the end round again to connect it to the stove. I decided to go with that method because after removing the damper (flapper part) it became evident I would have to remove some fire brick to avoid ovalizing the end of the liner, and I wasn't comfortable attempting that. Ovalizing it did make it a little tougher to get it shoved down the flue, but with a little brute force we made it work, and I feel good about being able to do the job ourselves.

Thanks everyone for your advice, which ultimately led to me spending an extra $250 (though it is nice knowing the job got done right). I'll post some pictures once I get the rest of the trim painted and put on the stove.
Click to expand...

good job on installing liner yourself .. now you've got two more issues coming .. making a block off plate and determining if Cat is still good.
a little late now for a tip to save $$$ on liner insulation .. then if you are having trouble with heat loss up chimney .. you can insulate entire firebox and damper area instead of a block off plate. https://www.hearth.com/talk/threads...neral-wool-instead-of-block-off-plate.124737/

you can purchase high temp mineral wool rated to 2000f to insulate entire firebox, damper for about $40 for one bale of mineral wood insulation. which also comes in 1in thickness in long rolls to wrap liner .. enough to do entire liner for about $40-$80.

there's an incredible markup $$$ for online liner/insulation prices vs buying local .. provided you are in a large enough metro to have large building supplier and fireplace warehouse. rigid double wall 8in stainless about .020 in thick was about $10ft for 4ft sections.. higher for elbows and shorter pieces.
 
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_CY_ said:
good job on installing liner yourself .. now you've got two more issues coming .. making a block off plate and determining if Cat is still good.
a little late now for a tip to save $$$ on liner insulation .. then if you are having trouble with heat loss up chimney .. you can insulate entire firebox and damper area instead of a block off plate. https://www.hearth.com/talk/threads...neral-wool-instead-of-block-off-plate.124737/

you can purchase high temp mineral wool rated to 2000f to insulate entire firebox, damper for about $40 for one bale of mineral wood insulation. which also comes in 1in thickness in long rolls to wrap liner .. enough to do entire liner for about $40-$80.

there's an incredible markup $$$ for online liner/insulation prices vs buying local .. provided you are in a large enough metro to have large building supplier and fireplace warehouse. rigid double wall 8in stainless about .020 in thick was about $10ft for 4ft sections.. higher for elbows and shorter pieces.
Click to expand...

I'm a little confused...are you saying I could have insulated the liner for $40-$80? If so, that hurts.

As for online purchases, anywhere I could find that wasn't an online purchase was way more expensive for the liner.
 
I don't think rigid double wall is a very good solution for an insert it would be next to impossible to get it hooked up right in the offset in the smoke chamber. And the insulation you are talking about is tat a ul listed chimney insulation? If not I don't think it is worth the money savings because you will not meet code and could void the liner warrantee. I am sure it would work but I think it is worth buying he right stuff.
 
a316co2000 said:
I'm a little confused...are you saying I could have insulated the liner for $40-$80? If so, that hurts.

As for online purchases, anywhere I could find that wasn't an online purchase was way more expensive for the liner.
Click to expand...

yes .. mineral wool rated to 2000f is material used for liner insulation. follow link in above post for rest of details.

DSC03982.jpg
 
I have seen that thread yes but I don't see that it is ul listed. Like I said I am sure it is fine but if it isn't ul listed there is a very good possibility it will void the warrantee. As well as not technically meet code which if you had a prick of an inspector he could fail you for it. I am not saying you cant use it I am sure it is fine I am just saying I would not use it unless it is tested for that application. All of the install directions I have seen call for a ul listed chimney insulation to be used if you need to insulate.
 
bholler said:
I don't think rigid double wall is a very good solution for an insert it would be next to impossible to get it hooked up right in the offset in the smoke chamber. And the insulation you are talking about is tat a ul listed chimney insulation? If not I don't think it is worth the money savings because you will not meet code and could void the liner warrantee. I am sure it would work but I think it is worth buying he right stuff.
Click to expand...

you are right that rigid liner is harder to install. one almost has to purchase extra pieces of different lengths to solve final connection puzzle.
final result is better due to thicker .020 stainless used all joints without locking tabs are screwed down.

IMHO a rigid liner is superior to a thinner flex liner. but is harder to install. believe it or not .. costs was much less due to buying all materials local. 16ft of double wall 8in stainless rigid including elbows and short sections costs right at $220 with tax. two bales of mineral wool 2000f insulation costs $90 with tax.

mineral wool used is rated to 2000f which the exact specification used for liner insulation.

it's made in all sorts of configurations from long 1in thick rolls to 2in x 24in x 48in and 4in x 24in x 48in , etc.
what I used had no backing .. much easier to wrap around liner and stuff upward 2-3 ft upwards past damper.

650C rated 8in stainless liner uses 2in of 2000f rated insulation inside a 12in diameter outer liner.
what I've done way exceeds 650C temp ratings .. inside an rock/mortar chimney that's several feet thick.
 
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I have no doubt that it is safe and probably exceeds insulation requirements but with out a ul label an inspector could fail it. I agree about rigid being slightly more durable but we use heavy flex which is made from .015" metal I don't think that using rigid is worth the extra trouble for the slight advantage in thickness.
 
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