Interior chimneys and insulation.

[karl]

There has been alot of talk lately about how the heat lost through an interior chimney is recaptured in the rest of the house. I was outside fetching wood and I looked up at the roof and I was kinda surprised. This is a concrete block chimney that is faced with granite blocks. And the granite blocks are a good 6 inches thick. The whole roof is covered in snow except by the chimney. I have a 6" liner and a blockoff plate, but no fireproof insulation above or around the insert.

I know people have said their block doesn't get anything more than warm. I think that's because the block is pretty good at wicking heat away and not getting hot.

I think there is alot to be gained by adding insulation above and around an insert.

 

[pgmr]

I didn't realize that Huntington was so high in the mountains...snow in May!

 

[karl]

No. That was today. The date on the camera is wrong. lol I am at about 1200 feet elevation thought. We call that a hill not a mountain,

 

[jbrown56]

Karl, All manufactuers say the liner should be insulated to retain the heat within the pipe itself. I would venture to say that most don't do it because it so difficult to get the liner down the existing flue. My chimney is an interior chimney, and like you, the roof is melted around the chimney. I could've poured loose fill insulation and probably should've, but I didn't.

 

[billb3]

My oil burner chimney will look just like that.

The sun will warm those stones up enough, too.


I doubt if the stones/bricks are wicking enough heat "out" as a window.
I rarely see snow built up on my skylight, either.

 

[karl]

We have been overcast for three days here. The snow has fallen since then. It's actually foggy out right now since things are starting to warm up. So, I don't think the block is getting warm from the sun.

I also don't think that an insulated liner would help. It doesn't matter if the heat is going up through the liner or through the chimney, it's still gone.

The fireplace itself is a big unisulated part of the ceiling/roof. Just like if you went up in your attic pulled up about 20 square feet of insulation.

I have a heatalator fireplace. That's just metal with a negliable R value. The R value of concrete block is about 1. And now I have stuck a big hot insert in there. I think alot of the heat from the insert itself is just going straight up. I have a block off plate, but still that's just sheet metal with no insulating properties.

I guess I'll have to wait until next year, after I put some kaowool in there to insulate things.

 

[DriftWood]

Stove heat in the house goes up. Pack as much isolation in to the attic above the stove as possible. keep it a few inches from the out side of the chimney though.

 

[woodsie8]

What is "loose fill insulation", as mentioned here? Wondering if after I do the install, I should just add the dang insulation myself, since I can't really find anyone to install the way I would like............