i wash with lukewarm water but always do my last rinse with cool/cold water...i think warm is ok, but i wouldnt wash with scorching hot water, or the same temp i wash my body with
Don't quote me, but from my understanding you should shampoo with warm water because it will help open up the hair cuticle so you can really get in there and clean it out. Then after you apply conditioner you should rinse with cold water to re-seal the cuticle.