A dual-channel fluid temperature control apparatus controls temperature of cardiac fluids during surgery using power from an electrical convenience outlet having a power limit. A first pump receives a first heat exchange fluid to selectively pump the first heat exchange fluid within a first circulation channel. A second pump receives a second heat exchange fluid to selectively pump the second heat exchange fluid within a second circulation channel. A first heater unit comprises a first plurality of independently actuatable heating elements each having a respective power consumption. A second heater unit comprises a second plurality of independently actuatable heating elements each having a respective power consumption. A controller selectably actuates the first and second pumps and the first and second pluralities of heating elements to selectably heat or cool the first and second heat exchange fluids such that power draw of all activated pumps and heating elements is maintained within the power limit.