Abstract: A fireplace room heater means comprising a hooded shell for mounting in a fireplace flue and comprising shell means forming an enclosure and with intake and exhaust air manifold chambers formed therein. An inlet port is in communication with the base portion of the intake manifold and an outlet port is in communication with the upper portion of the exhaust manifold, and a plurality of duct means extend across the flue area interposed between the intake and exhaust manifold chambers. The ducts are arranged in rows, with the individual ducts forming the rows being staggered from the individual ducts in adjacent rows, with the ducts extending along an inclined axis from the inlet to the outlet. A top row of ducts extends across and couples the upper end portions of the manifolds, one to another.