Direct vent fireplace venting uses a coaxial pipe system (small pipe within a large pipe) and draws combustion air from the outside through the outer pipe. An inner pipe vents the exhaust. Can either vent out the top or out the back, for installation versatility. Can vent horizontally through an outside wall, or vertically through the roof - no chimney required! Ideal for adding warmth & efficient heating to a cold room. Most are certified as gas wall furnace for highest efficiency. Zero clearance to combustibles. Convenient to install, space-saving depth, but requires finishing such as a mantel and surround. Suitable for well-insulated homes or homes with no existing chimney. Always have an enclosed front. Best choice for newer, more air-tight homes. Efficiency