Abstract: For a shower for a household, dormitory or the like, which typically has a limited volume of boiler-heated water available for use, the cold water input to the shower is passed in heat exchange with the discharging tepid water to thereby convert same to a lukewarm water source, the temperature change being typically a 15 to 25 degree rise, whereby significantly less boiler-heated water is required for preparing a suitable tepid water mixture confortable for showering. The aforesaid significantly prolongs the showering service use of the system and, since less boiler-heated water is consumed, correspondingly lessens the fuel consumption of the boiler.