The ideal zero clearance to replace mine…but would a wood stove be better?

[Alaska Lance]

Hello all, I’m grateful after so much time to discover this resource,
In 2016 I moved into the custom house that I and my builder friend designed and built. The steep pitched roof and small footprint made a freestanding wood stove impractical, so we built a hearth and a chase on the north facing wall for a zero clearance wood burning fireplace. I was looking at several costly models boasting great efficiency at the time when fate delivered me a mixed blessing. Just up the street someone was parting with their Majestic “built-in fireplace” and I could have it for free. It was installed. For years there have been many cheerful fires that were beautiful and romantic, but, the following negatives were also true: there was no outside air kit, no way to control the speed of combustion, it greedily shlurped firewood while obviously sending most of the heat up the chimney, the blower would loudly heat the 1,100 sq. ft. house with a good fire provided it was nearly constantly fed, and when not in use, the unit was a really bad heat-sink. I think this model was one of the prototypes. It’s old.
I just discovered I no longer have the installation literature and that the user manual covers 19 different models. I thought I could post my exact model with my exact dimensions, but I can’t. For what it’s worth I think it’s an MBU. The chimney is an 8” S-4 Selkirk. The face of the fireplace is 41 or 42 inches wide...I’d have to take some things apart to know exactly. The concrete hearth and wood chase we built are very spacious and I’m sure both can accommodate newer models which I think are generally smaller though way more efficient. I think I could also shove a freestanding wood stove half way in there if I built out the hearth a little more, and I’m very open to that if the efficiencies are significantly better.
This Majestic has to go.
The ideal replacement is a zero clearance wood burning fireplace that:
-fits existing dimensions very closely
-heats the space very well
-is very efficient
-has outdoor air and a way to carefully control combustion
-you can load at night and it won’t burn out til morning
-a glass door for viewing the fire
-allows me to use my existing two stories of chimney rather than dismantling and reconstructing the entire thing, probably a real pipe dream, pun certainly intended.
If these zero clearance wood burning fireplaces aren’t actually that advanced to accomplish the above I’d love someone to tell me so, because I’d happily get a radiating wood stove with a glass door in that space if it the best way to heat my home efficiently with wood.
Thank you in advance to anyone taking the time to read this post and think about my situation. More photos to follow from my other device.

 

[Alaska Lance]

Pics of the hearth below with some measurements. The last pi’s is my temporary heat sink solution: an alpaca blanket on a copper rod.

 

[kborndale]

Would that fireplace allow you to put in an insert? I'd go that route over a zero clearance if it can be done.

 

[begreen]

There are good EPA rated ZCs that will heat well. What are the dimensions of the current fireplace opening? What is the width and depth of the chase?

FYI, the wood mantel may be a clearance issue and need to be raised, trimmed, or replaced.

 

[webby3650]

We replace existing zc boxes with the Kozy Heat Z-42. It’s usually a really good fit. As far as reusing your pipe. If it’s able to be lift and then set back down on the new fireplace. Then you’ve got the issue of it being approved for new fireplaces, it likely isn’t. Also, many of the modern fireplaces use 6” or even proprietary pipe.