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.).
1 Inserts cost $1,200-$2,900, with professional installation adding another $600-$1,000.  A direct-vent gas fireplace doesn't need a chimney and is a way to add a fireplace where there isn't one. Installation is through an outside wall, and a pipe-within-a-pipe feature lets air in and exhaust out with just one vent. Direct-vent units average $1,200-$3,200, with installation running from $600 for a basic hookup to $5,000 or more for a fancy fireplace surround, according to Hearth.com .