Abstract: A heating and cooling system incorporates a heat pump that operates conventionally with air drawn from outside the system through its condenser coils that remove heat to the exterior for cooling. In the heating cycle, the condenser motor blower stops and reverses rotation. Outside air is drawn in by the condenser fan, is circulated across the diesel engine and generator, and is blown through the condenser coils outside of the unit. In the heating cycle, a circuit monitors the temperature of the compressor coil and controls the speed of the condenser motor. The heat recovery method of the system maintains power input to heat output ratios in excess of 2:1, even at low outside temperatures. The recovery method also allows the system to operate without defrost cycles. This system may provide auxiliary power, block heat, and battery charging, utilizing a small diesel engine and generator components, and can be installed within a truck, bus, boat, cabin, camper, and the like.