Liner Insulation 1/2 vs 1/4 vs None

[leeave96]

I have been searching/reading a lot of posts on liner insulation and have found that some use 1/2 inch insulation around their liners and others don't use any insulation at all!

What about 1/4 inch insulation?

I've got a chimney that has a clay liner with an ID of 6-5/8 and while talking to tech support for a liner company to figure out the total OD of their liner and insulation, they suggested I use a 5.5 inch liner with 1/4 insulation rather than tear out my clay liner. The chimney is interior to the house.

Any thoughts?

Thanks!
Bill

 

[BrotherBart]

I am over here in the Northern Virginia flatlands and I have two uninsulated 5.5" liners in my tile lined masonry chimneys. One 21' and the other north of thirty feet. Both have great draft. In fact the tall one has too much draft.

The 5.5" with 1/4" insulation should do a fine job for ya. If the chimney is tall enough.

 

[leeave96]

I think the liner/chimney height would be about 16 feet.

Thanks!
Bill

 

[pen]

or you could insulate using loose fill insulation such as vermiculite.

pen

 

[Renovation]

Isn't flue insulation useful to keep a flue warmer in an external installation, but not much benefit in an internal chimney, which is kept warm by house heat?

If so, "none" might not hurt you.

 

[formula_pilot]

As a point of reference, I have 1/4" insulation on my 6" rigid ovalized liner, because that is all I had room for with a 6.25x10.5 ID clay liner. The chimney is 15' tall, with a rear exit stove and 20" horizontal run, and the draft is quite good once it gets warmed up. Overall I am pleased with the result on what is considered a borderline install due to the height and the horizontal run. On mild days we keep the side door cracked until the fire is established, but now that it is getting a little colder the fire gets established much easier. I would not be afraid of using only 1/4", if that is all you have room for.

 

[burntime]

I have about 16ft and had it uninsulated and insulated. Chimney is in the middle of the house. It absolutely operates better with the insulation AND block off plate. It was like there was a third more heat...

 

[Renovation]

I have about 16ft and had it uninsulated and insulated. Chimney is in the middle of the house. It absolutely operates better with the insulation AND block off plate. It was like there was a third more heat...

What's a block off plate?

I wonder why it works better? The insulation traps the chimney heat, and heats up the chase/chimney?

 

[burntime]

It seals the base of the chimney just like the top plate. Search the forum and there are arguments pro and con. It makes it safer too. I did it for the safety factor and was estatic about the performance boost. If you are in a warm climate it will not make a huge difference in my opinion. In MI, yep, you gotta have it!

 

[btuser]

I think the liner/chimney height would be about 16 feet.

Thanks!
Bill

I'd go with the insulated liner 5.5", but that's because its what I did. I think the insulation helps a lot to heat up quick and keep it hot.

 

[ecocavalier02]

just go with the 1/4 inch. you put that 1/2 on there and you be cursing the whole time pulling that thing down the chimney. lol i cursed and i did the pour after. mine was a 6 inch in a 6 1/2 clay liner. and it was still fun.

 

[leeave96]

So is the purpose of the insulation to keep condensation from forming on the liner or to protect the original chimney from heat off of the liner during a flue fire?

Is insulation required where the original clay liner is intact?

Anyone had a flue fire in their stainless steel liner?

Thanks!
Bill