Summary For auditory integration (AI) therapy, the largest body of literature relates to its use in autism. Several systematic reviews of AI therapy in the treatment of autism found limited evidence to support its use. No comparative studies were identified that evaluated the use of AI therapy for other conditions.
The actual cost to install a gas fireplace may vary depending on your location, the product selected, complexity of the installation process, additional accessories purchased, and other options. 1  Top vented gas fireplace inserts cost $750 to $3,000, and installation adds another $500 to $1,000. Top vented gas fireplace inserts cost $750 to $3,000, and installation adds another $500 to $1,000. 2  Direct-vent gas fireplaces cost $1,000 to $3,500, plus $500 to $1,000 for installation.
1 They cost about $400-$1,500 plus installation of the gas lines and any desired mantle or surround. 2  Some states do not allow the use of ventless fireplaces or restrict their use. 3  Some ventless models require you to keep a window open while using the fireplace. Inserts cost $1,200-$2,900, with professional installation adding another $600-$1,000. 2  A direct-vent gas fireplace doesn't need a chimney and is a way to add a fireplace where there isn't one. 3  Installation is through an outside wall, and a pipe-within-a-pipe feature lets air in and exhaust out with just one vent.