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.).
Converting existing fireplaces to gas is the least expensive option for homeowners and involves simply inserting gas logs. 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.