Insulate the chimney liner?

[FrugalFirewoodDad]

2nd winter in this house. Existing terracotta (clay?) chimney that was level 1 inspected last year and deemed good to go for fireplace use.
We used it a lot. Decided to get an insert.

Looks like we are going with an Lopi Evergreen insert, new 304 stainless flex liner as recommended by reputable installer. Do I argue for and pay up for:

a) the rigid straight liner?

b) insulation around the liner?

The installer said neither are necessary. Thoughts?

NJ. Will attempt to use this stove as the vast majority of our heating next year.

 

[sean donato]

Yes insulate the liner, kinda surprised the installer said it didn't matter. The guy I had oit before we replaced the chimney gave 2 options for insulation. Wrapped or a pored vermiculite concrete type stuff.

There's nothing wrong with the flexible liner.

 

[Ted Jenkins]

If you want your system to work well the flue needs to get hot period. The exhaust needs to rise quickly or there will be smoky conditions. So insulation or double wall what ever needs to allow for good drafting. Thanks

 

[FrugalFirewoodDad]

If you want your system to work well the flue needs to get hot period. The exhaust needs to rise quickly or there will be smoky conditions. So insulation or double wall what ever needs to allow for good drafting. Thanks

The fella who came to measure and do write up the estimate asked if I had any issues with the draft using the current fireplace. We never have. No issues, and thats with a much bigger volume of air to move. Looking over the chimney, flu, etc he said I dont think you need it. I'll bring it up again and see what the installer says/thinks.

It cant be a big ticket item, and seems like good practice.

 

[Mad Professor]

Get a flex liner so you don't have to hack up the fireplace damper/smoke box to install the liner. Do insulate the liner it will pull a better draft and heat up much faster avoiding creosote buildup.

I'd consider a stove as you will get a lot more heat than an insert.

I put a woodstove in my existing fireplace and installed a whole insulated SS 316 kit from Rockford. Get the cap with the kit to seal the flue from the top and keep water out. I have a T-connector for the stove and can remove the cap, tape a g-bag on the T-s cleanout and brush the flue in <1/2 hour. Rockford kits are UL listed and carry a lifetime transferable warranty. Shipping is free.

I have an old Warner stove and with the insulated liner I get hardly any buildup inside the liner burning dry hardwood and I do choke it down for overnights or when I'll be away for a while.

 

[slabMan]

Here is what I would call good advice, based on my trials and errors when it comes to existing masonry chimneys and 'inserts'...I agree, free standing stoves do put out more btu's, but if you already have a masonry chimney, get an insert and you will have more usable space in the room and go with the ss flex [as The Mad Professor said]. I would stuff rockwool insulation around the liner [the least expensive], but what is most important with inserts [I too have a lopi], is to put as much fiberglass/rockwool insulation around the insert prior to sliding it into your fireplace. Again, the more you make the heat take "detours" or delay's from 'finding cold', the more efficient your stove will be. I insulated as much as I could and also above the damper, that way the heat will radiate outwardly vs upwards. It is also important to insulate the ceiling above your insert as well. I made some copper panels for my Lopi trim shaped like a "speaker horn" [as heat and sound are very similar in radiant flow], but the copper pulls the heat outwardly into the room. It is for a rustic old cabin I have, but works very well. One other tip to save $$ is to go to your local "spa/stove" installer store and they usually have long flex 6" sections of ss in the scrap bin out back [amazing what they toss in scrap IE fairly new wood stoves, ss flex, caps, flashing,etc.]. I frequent my local stove installer and buy the guys lunch in the warehouse to show my appreciation every time I get some useful materials [copper incl]. I made the hearth of mainly Ultra Mafic [Amphibole's] rocks that have a thermal capacity just less than soapstone, so after the fire is out, the thermal mass still radiates heat for a couple of days. Anyway, I hope this might be some useful info for you and your new purchase.

 

[Be Stihl]

Yes insulate the liner, kinda surprised the installer said it didn't matter. The guy I had oit before we replaced the chimney gave 2 options for insulation. Wrapped or a pored vermiculite concrete type stuff.

There's nothing wrong with the flexible liner.

This!