I would estimate 27' to the top of the vault.

. . and about 7' wide and 28" deep, with half inside and half outside.

how could I recreate the feel of this room with fireplace on a smaller scale?

We are building a new home but retiring I want to scale down but have impact. HELP.

The real key element to this room is dissolving the line between inside and outside with a full wall of glass. No window treatments. Just glass.

Not everyone is really comfortable with that approach, or has a piece of property where it is practical.

The second thing that makes this room remarkable is the basic geometry and pleasing patterns in the structure itself.

Another thing that is important is the use of bare, honest elements: visible steel, stained wood cladding and beams, the visible HVAC duct and the stone fireplace.

If you can design your new home keeping these elements in mind, the scale won't really matter so much. The simple honesty of the fireplace design will look good in any home.