A steam sterilizer for sterilizing instruments and devices, said sterilizer comprised of: a vessel having an inner wall and an outer wall, said inner wall defining a sterilization chamber, said outer wall spaced from said inner wall to define a cavity surrounding said sterilization chamber; a heating element disposed in a lower portion of said cavity, said heating element for vaporizing fluid in said cavity; and a fluid circuit connected to said vessel, said fluid circuit for conveying fluid to said cavity, for conveying steam from said cavity to said sterilization chamber and for exhausting steam from said sterilization chamber, said fluid circuit including: a conduit fluidly connecting said sterilization chamber to said cavity, a valve disposed in said conduit for controlling the flow of steam from said cavity to said sterilization chamber, a boiler pump for conveying a fluid to said cavity of said vessel; characterized by: a heat exchanger; a first line (204, 222) for draining steam from said sterilization chamber, a portion of said first line (204, 222) extending through said heat exchanger; and a second line fluidly connecting said boiler pump to said cavity, a portion of said second line extending through said heat exchanger wherein heat is transferred between steam in said first line (204, 222) and fluid in said second line. a vessel having an inner wall and an outer wall, said inner wall defining a sterilization chamber, said outer wall spaced from said inner wall to define a cavity surrounding said sterilization chamber; a heating element disposed in a lower portion of said cavity, said heating element for vaporizing fluid in said cavity; and a fluid circuit connected to said vessel, said fluid circuit for conveying fluid to said cavity, for conveying steam from said cavity to said sterilization chamber and for exhausting steam from said sterilization chamber, said fluid circuit including: a conduit fluidly connecting said sterilization chamber to said cavity, a valve disposed in said conduit for controlling the flow of steam from said cavity to said sterilization chamber, a boiler pump for conveying a fluid to said cavity of said vessel; a conduit fluidly connecting said sterilization chamber to said cavity, a valve disposed in said conduit for controlling the flow of steam from said cavity to said sterilization chamber, a boiler pump for conveying a fluid to said cavity of said vessel; characterized by: a heat exchanger; a first line (204, 222) for draining steam from said sterilization chamber, a portion of said first line (204, 222) extending through said heat exchanger; and a second line fluidly connecting said boiler pump to said cavity, a portion of said second line extending through said heat exchanger wherein heat is transferred between steam in said first line (204, 222) and fluid in said second line. a heat exchanger; a first line (204, 222) for draining steam from said sterilization chamber, a portion of said first line (204, 222) extending through said heat exchanger; and a second line fluidly connecting said boiler pump to said cavity, a portion of said second line extending through said heat exchanger wherein heat is transferred between steam in said first line (204, 222) and fluid in said second line.