Our firplace damper, like most,, leak like nobodys business.

Now,, we are thinking about having a insert or those glass fireplace doors installed in a frame in the opeing anyways,,,,

so does it make sense to have a top damper installed also on the top of the chimney since the present damper isnt that good?

I am thinking, why spend the $400,,,for the damper,,whereby, most of the heat should now not enter the firplace with the new surround there? Also,,,assuming we dont put the surround in,,,, and add the top damper,, how helpful are they, because, the air will enter the chimney anyways,, true, the top wil be sealed,, so there might not be the downdraft,, but how much of a difference would it make since the heated air will escape anyways?

Thanks a bunch,

Jim