Abstract: A condensing gas furnace/heat exchange system is provided which includes two subsystems. A first subsystem includes an outdoor coil, an indoor coil, a reversing valve and a compressor, and the heat exchange medium thereof is a liquid refrigerant, such as freon. This subsystem is operative in heating, heat-augmented heating and cooling modes of operation, and in the heat-augmenting mode of operation, gas burners provide additional BTU's to the system. The other system includes an outdoor coil, an indoor coil and a pump, but excludes a compressor or a reversing valve, and utilizes a heat-exchange medium such as water, ethylene glycol, glycol per se or a nonrefrigerant. The pump merely pumps the glycol through the system which absorbs heat/BTU's from the flames of the burner which are eventually transferred by the indoor coil to heat an associated dwelling or the like.

Abstract: A condensing furnace which includes an outdoor coil of the type having aluminum fins pressed to copper tubes through which a refrigerant is conducted. Heat is generated, preferably from a flame, and the relatively intense temperature (approximately 2200.degree. F.) is de-intensified before reaching the aluminum fins by generally sinusoidal de-intensifier tubes positioned between the flames and the fins of the coil. Since the de-intensifier tubes reduce the temperature of the flue of gases virtually instantly to approximately 50.degree. F., condensation forms not only upon the de-intensifier tubes but also upon the aluminum fins of the coil which prevents acidic deterioration and corrosion thereof, while at the same time maintaining extremely high Btu absorption.