I've been reading over all the topics here since I found the site a few days ago. Something I have yet to see, and it has been brought to mind since I have burned through a ton of wood the past few days with temps here in the teens, is converting/retrofitting my existing fireplace as an RMH. Not sure how well it would work if it can be done at all.
Here is what I have now. The front opening is approx 33" wide by 22" at the sides and 27" in the middle of the arch. If memory serves, the back of the firebox is about 25"-26" and the depth is around 18"-20". I would guess the height inside the fireplace is about 36" at it's highest. That is purely a spitball guess though. I would provide exact measurements but I think you can see why I didn't.
Thoughts?