{The First Condensing Vented Gas Fireplace Insert Certified for Use in the U.S The Mantis exceeds 93% efficiency - which means it uses about 35 percent less fuel compared to any other vented heater or fireplace system per Btu of heat in your room. This makes Mantis the ~greenest fireplace you can buy~. Because its inexpensive 1-1 2-inch PVC vent pipe can be run inside a conventional 2 x 4 framed wall, the Mantis ~costs less to install~ - in materials, time, and labor. The Mantis is the first and only vented fireplace that adds humidity to the dry winter air, making your home warmer and more comfortable. For all its advanced technology, the Mantis is amazingly easy to operate. Two on off buttons control the two burners, allowing you to set the temperature to low (front only), medium (rear only) or high (both burners). {What Makes Mantis Unique? Inside the Mantis a three-stage heat exchanger sends more than 93 percent of the heat energy into your home - not up the flue. While the temperature inside the combustion chamber may exceed 900 degrees F, the exhaust gas exits the flue at just 120 to 130 degrees F - as little as two feet away This makes Mantis ~the first and only condensing fireplace~, which means the exhaust is cool enough to run in PVC. The Mantis puts the green in environmentally friendly. Its power-vented heat-exchanger technology ensures the optimal air fuel mixture for consistently clean-burning operation. With its clean burn and super-efficient heat exchanger, ~the Mantis generates fewer greenhouse gases - CO and CO2~. The top and sides of the Mantis stay cool-to-the-touch - so cool, in fact, it earned a zero-clearance certification for installation against any combustible building materials. The dual burners deliver a total of ~28,000 Btu~. Operating the front burner alone lets you enjoy the ambiance of the attractive log set and gas fire without overheating the room. But, when the temperature dips, the Mantis rises to the occasion, switching on the second burner to produce maximum heat output.Prou