About this chimney draught excluders
Chimney Sheep 13 x 13 Inch Herdwick Wool Chimney Excluder
A large open fireplace is a very effective chimney: it pulls plenty of air. In winter that means a lot of the warm air in the room goes up and out, and a lot of cold comes down in its place. A thick wool pad in the throat of the flue reduces that flow without making a permanent change to the chimney.
This Chimney Sheep is the larger square size, 13 x 13 inches, made from Herdwick wool felt. The wool is breathable, which is the point: it blocks the draught but does not seal the chimney airtight, so the stack can still breathe. It is placed by hand and lifts out in seconds.
Measure carefully, because the opening in a large fireplace is often not square. Take the width and depth at the narrowest point you can reach, and choose the pad that is slightly larger so it seats snugly. As with every Chimney Sheep, take it out before you light a fire.