It depends on several things- if the kiva fireplace is to be a masonry fireplace, is there a footing under the existing floor to support the weight of the fireplace? How tall are the ceilings and is there a second floor above the fireplace floor? That determines the height of the chimney flue. Is there room to add a masonry backing behind the fireplace?- That is code.

There are various other items to consider but generally we estimate a ballpark price of $7,000 to $10,000 for a small fireplace addition.

I hope that answers your question and helps with your decision.