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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I am by no means saying you are wrong on either count I just don't see that it is worth fighting with rigid and as a pro I feel I need to use tested and approved products and I will always recommend that to others
 
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.

looking from a professional's point of view .. time is money .. I'd go for the easiest to install without short cutting quality.
which is heavy stainless flex ..

but for someone doing the job themselves. if it costs substantially less $$$ and delivers a safer installation ..
but takes 2x longer to install ... the lowest cost while delivering safest/best installation wins.
going with heavy stainless flex would have more than doubled my costs.

installing the rigid really didn't take much more time .. what took the most time was cutting out damper large enough to allow an 8in liner through with 2in of insulation. more planning was definitely needed to figure out exact pieces needed and where insert collar would meet.
 
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I agree with most of what you said completely accept that rigid is safer than heavy flex I don't think there is any difference in safety between the two. I do see a potential problem with the rigid in that due to the difficulty in hooking up the joints in the offsets it is very possible that you may not get them completely together which could be a safety issue further down the road. Also what brand of insulated chimney did you get 16' of for $220 that is one hell of a deal
 
I agree with most of what you said completely accept that rigid is safer than heavy flex I don't think there is any difference in safety between the two. I do see a potential problem with the rigid in that due to the difficulty in hooking up the joints in the offsets it is very possible that you may not get them completely together which could be a safety issue further down the road. Also what brand of insulated chimney did you get 16' of for $220 that is one hell of a deal

didn't mean to imply rigid was safer than heavy flex .. they are equally safe .. the safest claim was from doing an install using 2000f rated mineral wool insulation way in excess of 650C ratings. Class A liner rating no where comes close.

yes one needs to be competent enough to snap liners together solid and screw down everything else. it's solid! NO way it's coming loose.
final joints are sealed with 2000f gasket cement, then covered with 1 inch hi temp rope held in place with a custom stainless 2in band. then covered with 2in 2000f insulation .. followed by filling in all voids with 2000f insulation.

concrete blocks were placed behind insert to prevent 650lb Buck 91 from moving.
anyone that knows their stuff can quickly tell this install was done right!
 
sounds like a great install I just wouldn't ever want to do it. lol
 
From what you're saying it doesn't sound like the savings are all that significant for the liner. I ended up paying $385 for a 25' liner, appliance connector, and rain cap, with no tax and free shipping. Granted, I had to negotiate a little over e-mail with the ebay seller, but given how much longer my liner was and the inclusion of the rest of the kit I think I did well, and without the hassle of piecing together multiple lengths of rigid liner.

Where your advice could have definitely saved me money would have been in the insulation, but if that's 2 inches thick it wouldn't have worked well for me anyway. My flue was 11" x 11" and it was hard enough to cram the liner down it as it was. Adding insulation that thick would have made it practically impossible.

On that note, I may buy some roxul and line my firebox with it.
 
From what you're saying it doesn't sound like the savings are all that significant for the liner. I ended up paying $385 for a 25' liner, appliance connector, and rain cap, with no tax and free shipping. Granted, I had to negotiate a little over e-mail with the ebay seller, but given how much longer my liner was and the inclusion of the rest of the kit I think I did well, and without the hassle of piecing together multiple lengths of rigid liner.

Where your advice could have definitely saved me money would have been in the insulation, but if that's 2 inches thick it wouldn't have worked well for me anyway. My flue was 11" x 11" and it was hard enough to cram the liner down it as it was. Adding insulation that thick would have made it practically impossible.

On that note, I may buy some roxul and line my firebox with it.

what's the thickness of 8in liner purchased for $385 shipped?
when shopping what I found were mostly flex liner kits with .007in thickness stainless.
no question flex liner will be easier to install vs rigid ..

not everyone has the luxury of having access to a fireplace warehouse with decent inventory.
same for large commercial building supplier that stocks correct high temperature insulation.

mineral wool insulation rated at 2000f comes in several different thickness/shapes including 1in rolls.
Lowes can order correct insulation but they will need help in finding part numbers/descriptions.

DSC03989.jpg
 
what's the thickness of 8in liner purchased for $385 shipped?
when shopping what I found were mostly flex liner kits with .007in thickness stainless.
no question flex liner will be easier to install vs rigid ..

not everyone has the luxury of having access to a fireplace warehouse with decent inventory.
same for large commercial building supplier that stocks correct high temperature insulation.

mineral wool insulation rated at 2000f comes in several different thickness/shapes including 1in rolls.
Lowes can order correct insulation but they will need help in finding part numbers/descriptions.

DSC03989.jpg

I think it was .006...whatever the standard 1-ply SS liners are, but it met UL specs.
 
yeah .oo6 is the standard light wall liner thickness
 
Well yesterday it was about 32 degrees outside and VERY windy (20 degrees with wind chill) most of the day, so I figured it was a good day to test the capability of the stove. I came home on my lunch break and followed all the instructions I've read online for using catalytic stoves (got a nice hot fire going, let the stove heat up, then closed the cat bypass and air "intakes" on the front). I turned the heat off but left the furnace fan on to circulate the air throughout the house. It's a 2-story colonial and one of the two air returns is on the main level just outside the room the stove is in, so I wanted to see if this method helped move the air around.

When I turned the heat off it was 70 degrees in the house; when I got home a few hours later it was 68 degrees in the living room (which is located on the opposite side of the house with hallways in between, restricting the flow of air). I also went upstairs and it felt pretty comfortable up there as well. I have a 2-year old so when she got home I used a small space heater in the living room to bring it up a couple more degrees in there, but it only came on occassionally. The rest of the bottom level was plenty comfortable enough thanks to the stove. I don't have a thermometer in there but I would think it had to be at least 75 degrees.

Before bed I loaded it up as full as I could get it (also did this around 4:30 pm) and after about 20 minutes closed the cat bypass again. I turned the heat on just in case, but left the fan on full time (as opposed to keeping it on auto) to keep moving the heat from the stove around. This was at 10:30 pm. This morning I woke up and came downstairs at 7, and the blower to the stove was still on putting out a small amount of heat. A couple mostly burned logs remained in the stove from the night before, so I put some kindling in and loaded it up again, 20 minutes later closed the cat bypass, and told my wife to turn the heat off when our daugther wakes up and comes downstairs.

Overall I'm pretty happy with my free stove and $625 insulated liner kit. I'm still kind of learning how to work the stove (though I think I have a pretty good handle on it), but I was able to get a load to burn for 8.5 hours and be the primary heat source for a 2,000 sqft, 2-story house with a floor plan that is anything BUT open, all in sub-30 degree weather. Oh and I'm using what I was told is seasoned oak, but I believe it to be poplar. Before and after pictures still to come for anyone interested.
 
Poplar is much lighter than oak and has a clear, greenish tinted grain. If that is poplar you are going to be in for a big surprise when switching to oak. Just be sure the oak has had a couple years of seasoning since it was split and stacked.
 
yes .. mineral wool rated to 2000f is material used for liner insulation. follow link in above post for rest of details.

DSC03982.jpg

No, it isn't. Liner insulation wrap is ceramic fiber. Mineral wool isn't rated for use at 2000. It melts at that temp in its purest form.

It is a discussion of technicalities. You will not find a manufacturer of mineral wool that will tell you to insulate your flue with it.

It does meets code in Canada as a material for a block off plate, butt in that instance, it is open to cooling on one side.
 
The material you are linked to is used to provide additional escape time in the event of a structure fire. It is intended to be used for this purpose once, during a fire. It is tested to ASTM E136, which you can look up. It is not tested in the application you are describing.

The test for liner installations involves repeated chimney fire simulations, and in Canada involves 2100F temps. Insulating a liner involves following the manufacturers instructions, otherwise you are experimenting, and do not meet the ULC specs.
 
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Here is a link to a product that is intended for chimney liner use. You will note that it specifically states a max continuous operating temperature vs a melting point.
http://www.morganthermalceramics.c.../kaowoolblankets-kaowoolblanketszrenglish.pdf

Yes this is the proper type of insulation intended for use with a chimney liner, with a foil backing. This insulation, called many different names by many different manufacturers, is UL listed with the use of a chimney liner and being safe in the event of a chimney fire. Chimney fires can exceed 2100*. This insulation is rated to exceed that.

A wool type insulation, or the like, is great for block of plates. It is not UL listed with the use of a chimney liner. It sill can help definitely with keeping the flue warm, but it is NOT UL listed with a chimney liner.
 
ChimneyLinerJames has it right, the need for a 2000 F rating is to meet UL standards in the event of a chimney fire. Yes it's a worse case scenario, but that's where the rating comes from. Not everybody installs to code.

My guess is if you had a chimney fire, no insulation might be better than the wrong insulation.
 
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my liner is insulated to be safe in excess of 1,100C with added safety of being inside a masonry fireplace several feet thick.

Would love to see pics of a fireplace "several feet thick" much less the chimney on it which is where the concern would be.
 
my liner is insulated to be safe in excess of 1,100C with added safety of being inside a masonry fireplace several feet thick.

You may be right that it is safe but it was never tested by any one for that purpose and it is not approved for it. Even though it migh be safe it should never pass an inspection and if there were a fire your insurance company will likely deny your claim due to using unlisted materials in the install
 
I don't think anyone is saying that it is not safe. But we are all saying it does not meet code and telling other people to do installs that do not meet code is irresponsible. And by the way you may have several feet of masonry on the sides but not on the front where the roof framing meets the chimney it looks to me like you only have about 6" to 8" there.
 
Somewhere in all of this the OP's question has probably been answered.
 
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