Chimney sweep smoke test - GIF

[nova_robotics]

Just imagine how much heat is escaping from your house when you don't have the fireplace lit. A fireplace is one of the biggest holes in the building envelope.

[bob_3000]

Just imagine how much heat is escaping from your house when you don't have the fireplace lit. A fireplace is one of the biggest holes in the building envelope.

That's why both of mine are blocked with pink bat insulation held up by plywood until the rare occasion they get used.