This type of fireplace venting uses economical "B-vent" pipe for a natural drafting (warm air rises) chimney. Uses room air for combustion and venting terminates above the roofline (like a furnace). More decorative, lower efficiencies. Zero clearance to combustibles. Relatively easy to install, space-saving depth, but requires finishing such as a mantel and surround. Large traditional fireplaces in clean-face or circulating models. Ideal for locating anywhere in the home where B-vent can be installed. Less Cost than Direct Vent. The Hearth, Patio & Barbecue Association recommends the installation of a carbon monoxide detector with all gas hearth products. Pro - Economical Con - Low Efficiency