Single vs double wall pipe?

It helps to keep the chimney clean. Especially with a cat stove. If you have no clearance issues then you can save money and go with single wall.

I like an adjustable piece in there to make hook up and cleaning easier.

Aeneas61 said:

We have about 13 feet from the top of a brick masonry heater/cookstove

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Which is it?
The reason I ask is if its a true masonry heater (with all the up down, in and out passages for the flue gasses) you may want to spend the extra coin on the double wall being that the flue gasses will already be pretty cool leaving the unit.
If its a traditional cook stove then either or can work but I would lean towards the double wall dvl pipe due to keeping the flue gasses hotter keeping the chimney cleaner / more efficient

If it's the kind of high mass masonry heater designed to burn short, hot fires, then I would go single wall. If it's the kind of cook stove that you want to be able to throttle back and burn at a lower level for hours, then go with the double wall.

Aeneas61 said:

Heck, some just use old solid steel pipe from a construction site, why is a house physically so much different?

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Because people live in houses.
You gotta do it right and safe. I vote double wall for most home installations. The stove will last for years. A couple hundred more is cheap for years of use.

Even if your clearances are fine with single wall, double is best for most applications, mostly for the creosote issues mentioned above. The longer the pipe, the cooler it gets and the more hardened creosote can form. Creosote gasses condense at about 250F which is pretty cool. Be sure to get an appropriate flue thermometer whether double or single.

I'm sure there are some exceptions, like for a greenhouse or something, and some here will chime in with those. Whatever you do, be sure to follow the manufacture's manual and you should be fine. So far it sounds like you're doing good and asking the right questions.

I'm trying to imagine what your masonry heater/stove looks like. You say the pipe comes out of the top. Is it like this?

Low-efficiency stove answer: You only need double-wall if your clearances require it. Flue gasses will be hot enough that the performance differences between the two are not a factor.

High-efficiency stove answer: Double-wall pipe will help keep your already-cool flue gasses warmer, provide maximum draft, and help to prevent the condensation of creosote in your chimney. The number one complaint of folks switching from old pre-EPA stoves to modern efficient stoves is that their draft is lacking, so do not ignore this factor.