What does liner insulation get me?

[Vic99]

So I've been burning my HS homestead nearly 24/7 for a month now and I love it.

When we had the install done, we vented out of a preexisting chimney than runs up the center of my 1920 house. A new 6" steel liner was installed. The home inspector insisted that the liner be insulated . . . I believe they used rock wool? It looks like a cross between cotton and fiberglass with a reflective foil-like backing.

What are the benefits or drawbacks of liner insulation? I am wondering if less heat is getting transferred to the brick and I am losing some heat.

 

[derwood]

Insulation gives you a couple of things. First is increased safety factor. The inspector rightly insisted on insulation wrap since your new stove has the potential of sending much more heat higher up the stack than a fireplace would. Pyrolysis over time lowers the combustion temp of any wood that may be lurking where it shouldn't be in the chimney. You simply can't rely on wood not being there and that the chimney was originaly constructured correctly. The insulation blanket keeps the temp from radiating out.

The second benefit is that with the insulation blanket keeping the temp from radiating out, it also works to keep the stack temp higher which results in less creosote build up. This too is a good thing.

 

[JimWalshin845]

Last week saw an intersting show on "How Its Made".... they were fabricating double walled stove pipe. Yep... looked like rock wool they were packing in.

As said earlier, hotter flue will help alleviate creosote build up and give better draft.

 

[derwood]

As a side note, I was up in WI visiting my family. My brother said that in his last trip to the attic he was looking at how his gas furnace was vented. And he was venting about the installation when the house was built because the chimney was off by about 4" which meant they cut out a bottom section of the roof truss to make space and left it hanging there.

This reinforced for me erring on the side of caution. I didn't have to insulate my liner but I did.

 

[stonehouse]

I'm on an exterior chimney brick chimney, 195 years old. I have 2 uninsulated SS liners in one chimney. My sweep said that because I have one for the stove and the other for the furnace and more importantly the water heater, that I don't need insulation. It was because of the water heater running that I don't need it. He said the second liner with the water heater will prevent the stove liner from cooling too soon and building up creosote. Sounds like you got a good install.

 

[Vic99]

I concur, less creosote build up is a good thing . . . just wish I didn't have to lose out on some heat. Rather be safe, though.

thanks.

 

[precaud]

What are the benefits or drawbacks of liner insulation? I am wondering if less heat is getting transferred to the brick and I am losing some heat.

In operation, insulation maintains a stronger draft at lower burn rates. I now have two liners - one 16' in an exterior wall chimney and insulated, and one 28' in an interior chimney but not insulated (and almost twice as long). They both pull great with high firing, but the insulated one pulls much better when damped down. The results surprised me.

 

[begreen]

Seems like the insulated liner got you a passed inspection. The rest is gravy.

 

[jtp10181]

I'm on an exterior chimney brick chimney, 195 years old. I have 2 uninsulated SS liners in one chimney. My sweep said that because I have one for the stove and the other for the furnace and more importantly the water heater, that I don't need insulation. It was because of the water heater running that I don't need it. He said the second liner with the water heater will prevent the stove liner from cooling too soon and building up creosote. Sounds like you got a good install.

I hope you don't have 2 SS liners side by side in the same flue cavity. Also, the flue temp is only a beneficial side effect of the main reason for insulating. Without the insulation most liners do not meet UL 1777 approval.

 

[bcnu]

Hey C..99, glad u lov ur Homestead. Same here.
I'm watching the stove top thermometer cruise slowly toward the 400 degree range, as that's where it really seems to begin radiating serious heat to the house. Morning outside temp is hovering around 35 and we are going to get some snow today - which doesn't happen often in the Portland(Oregon) area. The mountains have picked up over 100 inches this past week. I have an uninsulated SS liner in an inside masonry chimney - will check the creosote when I clean it next summer. Happy burning!