Abstract: An air conditioning system which reduces energy consumption by disposing of the waste heat to a low temperature heat sink, at the same time recovering useful energy. An auxiliary liquid cooled condenser is connected in parallel with the air condenser of a conventional vapor compression air conditioning system through a valve located between the compressor of the existing system and the condensers. When the valve is actuated the refrigerant of the air conditioning system is routed from the air condenser and instead flows through the liquid cooled condenser assembly in heat exchange relationship with a body of fluid which is at a lower temperature than the ambient air, such as water from a swimming pool or from a municipal water supply. The valve also serves to exhaust refrigerant from the unused condenser. Maximum energy conservation is achieved by use of the total heat content of the refrigerant rather than only the high-temperature heat as in those prior art systems designed as a principal heat source.