washing cloth diapers

Washing cloth diapers is rather confusing to me. Should I wash them with cool water or warm water? I read in many cloth diaper's blogs that we need to wash the diapers in warm or hot. But my washing machine just use cool water. It's really tiring and tasking to boil water and to fill up the tub. I don't have the warm shower. Hmmm...better start asking around bout this.