Yes, This is what I also did with our last house.
It came with a 'canned' fireplace. Kinda tacky, and provided ZERO heat into the room. I yanked it out, and reframed for a Zero-clearance wood stove, the FireplaceXtrordinair. It looks like a fireplace, but has the efficiency of a woodstove, transmitting most of the heat out into the room rather than up the chimney.
Heres a pic...
J F Graham wrote:Lisa, I have installed a few fireplace inserts in the past, and don't think it's possible in the situation which you describe. First with the damper being only 2 to 3 inch you would never fit a 6" liner through it. And I see no way of securing the flex pipe to the chimney. You're only option, in my opinion is to remove the existing units. Install a proper fire back, to code and install whatever freestanding unit you desire.