Chimney Balloon large

Q: Jason, I have a masonary fireplace that appears to have no chimney damper. I have measured the rectangular area after the firebox and it’s approximately 25.5″ X 9.5″. What size Chimney Balloon would be best suited. thanks. – RG

A: RG, For an area that is 25.5″ x 9.5″ I would recommend the 30×9 Chimney Balloon. Chimney Balloons are slightly oversized by their inflatable nature, and a half inch will not make a difference when you install it. – Jason