Similarly, you may ask, can chimney balloons cause damp?
Alternatives to the Chimney Balloon You could block your fireplace with a board or bricks or seal the top of the chimney but you then can't use your fire whenever you feel like it. This will also cause your chimney to become damp since the bricks aren't breathing.
Besides, how do you use a chimney sheep?
Just push the wool head into the narrow part of the flue. You may need to tug it down gently to ensure a good fit. That's it. When you want to remove it, pull gently in case there is any debris collected on it that has fallen down the chimney.
The Chimney Balloon is made of extraordinarily tough plastic. But when it gets hot, it will just shrivel and fall into the grate. Other inflatables are made of PVC which expands and gives off fumes – the Chimney Balloon is by far the safest!