Hansen's disease, also known as leprosy, is a chronic bacterial disease that primarily affects the skin, peripheral nerves and upper airway.ansen's disease, also known as leprosy, is a chronic bacterial disease that primarily affects the skin, peripheral nerves and upper airway.
1 Direct-vent gas fireplaces cost $1,000 to $3,500, plus $500 to $1,000 for installation. 2  The cost of a ventless gas fireplace is $500 to $2,500, and while there are additional installation costs, you may pay extra for finish work (such as a mantle, marble surround, etc.). The cost of a ventless gas fireplace is $500 to $2,500, and while there are additional installation costs, you may pay extra for finish work (such as a mantle, marble surround, etc.).
These nonflammable logs look much like real wood, and come in vented and ventless types. Vented gas logs require a working existing chimney and cost from $300 to $550, according to CostHelper. Ventless gas logs do not need a pipe or chimney and cost from $350 to $600.Installation adds $200 to $350 extra to cover a licensed contractor and a new gas outlet.Another conversion method uses top-vented gas fireplace inserts, which may include fans and thermostats. These cost from $1,200 to $2,900, plus another $600 to $1,000 for professional installation.nother conversion method uses top-vented gas fireplace inserts, which may include fans and thermostats. These cost from $1,200 to $2,900, plus another $600 to $1,000 for professional installation.