Plastic chimney balloons work on some level, but they have several flaws. … Chimneys are there for ventilation so it figures that if they are blocked, your house doesn’t breathe like it should. This can lead to condensation and mildew – not nice. Do chimney caps affect draft? best chimney cap.

Are chimney balloons a good idea?

If you light a fire with the Chimney Sheep in place, the fire will smoulder and not draw properly, and it’s fire retardant so it won’t burst into flames, which is fine with an open fire but to be honest the Chimney Balloon is a safer bet for gas fires.

Are chimney Draught excluders safe?

These are made from a special tri-laminate material, that if exposed to heat will simply shrink and cause the product to fall out of the flue. Most dangerous of all are the cheap PVC inflatable chimney draught excluders, which will tolerate a greater amount of heat then suddenly pop releasing chlorine gas and PCB’s.