Warped, broken, or leaky dampers can cost you hundreds of dollars a year. Damaged dampers allow the comfortable air in your home to escape up the chimney flue, making for higher utility bills year-round. In independent laboratory tests, the Lymance Top-Sealing Damper retains as much as 90% of the air lost by a traditional damper. Its super-tight rubber gasket seal keeps cold air out and warm air in. Lymance Top-Sealing Dampers have been a popular energy-saving choice for years.