If the fireplace can now take the heat from a log fire then it can certainly take the greatly reduced amount of heat from a wood fire inside an insert. Check the caveats for the insert by the manufacturer as any safey issues will be spelled out to take them off the hook should there be any problems.
I would be most concerned about proper air flow to take the combustion gases and in particular, carbon monoxide, out of the insert and up the chimney. When I added an insert it had two stainless steel vents, one for incoming air and one for the combustion gases. I bought a CO monitor to plug into a wall outlet just to be safe.
I would be most concerned about proper air flow to take the combustion gases and in particular, carbon monoxide, out of the insert and up the chimney. When I added an insert it had two stainless steel vents, one for incoming air and one for the combustion gases. I bought a CO monitor to plug into a wall outlet just to be safe.