the area around the outside of the chimney is sealed tight. the hole cored, and then grouted in after the fact. its the cold air im talking about inside the chimney coming back into the house when the fire place isnt in use. I want to know if there is an insulated damper or something on the market to shut the chimney off so im not letting cold air in, or allowing warm air to escape inside the chimney itself. outside the circumference of the chimney is well sealed.

Ok, I couldn't understand how someone did such a bad job that cold air was getting in between the pipe and foundation. So I just don't understand how you are getting a stream of cold air.
Assuming you have your stove door shut, and you turn your air control down, leakage should be trivial...your saying its not? You have done these two things? and yes I have to ask.
Most all new stoves have a opening in the air control so that you cant fully shut the air off, this stops someone from having a really smoky fire, often its little more than a nickel size hole in the air control or some such sized opening.
this would likely be the only place through which your cold air could move, and it should be trivial...if its not trivial then the only way any serious volume of air could move through such a small opening is under pressure (negative). Your stove will need its own fresh air supply then, but confirm this. Find where the air supply to your stove is, such as in the pic where I added the fan...find the opening and put your hand there...can you feel cold air tumbling out? Light a match there, does it get blown out?

Ok, I couldn't understand how someone did such a bad job that cold air was getting in between the pipe and foundation. So I just don't understand how you are getting a stream of cold air.
Assuming you have your stove door shut, and you turn your air control down, leakage should be trivial...your saying its not? You have done these two things? and yes I have to ask.
Most all new stoves have a opening in the air control so that you cant fully shut the air off, this stops someone from having a really smoky fire, often its little more than a nickel size hole in the air control or some such sized opening.
this would likely be the only place through which your cold air could move, and it should be trivial...if its not trivial then the only way any serious volume of air could move through such a small opening is under pressure (negative). Your stove will need its own fresh air supply then, but confirm this. Find where the air supply to your stove is, such as in the pic where I added the fan...find the opening and put your hand there...can you feel cold air tumbling out? Light a match there, does it get blown out?

Yes, I keep the stove door shut, and the air control is always turned down. But the fact that I have a chimney open to the outside means that cold air will sit in the flue and will cool. Very noticeable during the cold months. The foundation walls are well insulated, its just that location of the chimney where its basically a pipe open from inside the house to outside. During the cold snap earlier, there was a bit of a downdraft from the chimney into the fireplace. This was corrected when I opened a window before starting the fire. The neg. air pressure built up inside the house equalized and I didnt get it sucking air in. When it warms up outside, the problem is significantly better. But....the fact remains I have a pipe, open to the outside, uninsulated, and allowing outside temperatures into my house when the stove is not in use. I could say the same for the summer time. When I try and temper my house with an A/C unit, I'll have this pipe open to the outside where hot air will be able to run in. Though the air control is turned off on the stove...I have a warm pipe now, and the air seal isnt perfect in the flue nor the stove. Just the nature of a wood stove.

you have me stumped then. No one I know of using wood for heat has the problem you describe or has mentioned it. That is double wall black pipe? I have to think you must have air movement through this system for it to be such a problem. I would take a insence stick or some such thing all over this stove to try and find air flow, has anyone else heard of such a problem?

also the air seal in the flu should be perfect. when I put the black pipe together I use high temp sealant to ensure its so.

I burn hard maple purchased at $85/face cord. I always have 3 years worth of wood stored on wood slats outside plus 5 or 6 cords inside my woodshed for use this winter. I order my wood during the winter for delivery in May and let it sit in the sun in a pile all summer long, before stacking it.
My son cleans my chimney every September.

This is just a shot in the dark, and maybe even a dumb question, but is the door gasket intact?

This is just a shot in the dark, and maybe even a dumb question, but is the door gasket intact?

Yes sir.

Its thermal bridging between the outside and inside through the foundation wall. Hence why I'm seeing if there is a damper or insulated damper i can install at this location. And also simply cold air coming down the chimney....and as it stirs it cools the air in the basement. Its not a wide open flow of air and I'm not freezing out...but its noticeable especially during the cold snap.