Chase or not to chase......

[ckarotka]

I'll start with the set up first.
15.5ft of chimney straight up through the ceiling of a ranch home
5.5ft single wall black pipe inside
6ft of triple wall ss in the attic
4ft of triple wall extends out of the roof and is UNchased (full outside exposure)


The stove performs best when the outside air is around 30 or higher up to about 45 °F
Big difference in stove performance from when the outside air is in the low 20's or colder
even on those cold days the draft is very good i.e. no smoke inside, no smell you wouldn't know it was burning if you didn't see it.
But I think it should be stronger for stove performance. In my area we have a normal sustained wind all year of around 15knots seems like more in the winter, some are calmer but that's an average. It;s the wind that I think is causing the rapid cooling effect.

After all the reading here and talking with this one stove guy who seemed to know his s***. This stove guy told me that instead of buying a bigger stove to get better burn times to buy a better chimney. I believe that the exposed section of pipe is losing heat to fast and slowing down my draft enough to make a noticeable stove operation difference.
If this is true I should chase in the exposed pipe, insulate the chase walls and cap. That's the easy part. I'd rather not extend it for cosmetic reasons. Plus if it is cooling down, extending it would just add to the problem.

The hard part is, knowing if my time and money will be well spent, and will I see a better stove performance when it's below 20 °F or colder.

Can anyone tell me from experience that this is the right thing to do?

 

[LLigetfa]

Replace the 5.5 ft of black single-wall with double-wall. Wrap the 6 ft of SS pipe in the attic with radiation shield. That should keep enough heat in to improve the draft.

 

[ckarotka]

Being a small stove and needing a bigger one I like the extra heat coming off the black pipe inside. If I can't fix the problem with a chase, I will definitely change to double wall inside. I guess I'm really hoping a chase will work because for me the labor and most of the material is free, I can easily do this in a few hours, built many a home.

 

[LLigetfa]

There's no point in heating the attic. Start by chasing in the attic section. It doesn't need to be pretty, just functional. Adding radiation shield and chase will make it warmer and safer.

My chimney is shorter than it should be. It doesn't go through an attic per se but rather through a walk-in closet. I ran it through a radiation shield between the floor and ceiling and also chased it with drywall.

 

[Backwoods Savage]

We run SS chimney all up the outside wall. No need for a chase here in MI but maybe it is colder in PA than MI. However I doubt it is colder inside the house. Hum.....

 

[Detector$]

It sounds to me like his point is that doublewall stainless class-A (thermofill insulated) chimney will be less susceptible to cooling than air-insulated (air cooled) triple wall. And, I agree in principle. I have ICC Excel class A with some type of asbestos-type insulation between the two layers. Once I get the chimney up to temp I bet it stays that way for a long time.