I have left the CamelBak insulated bottle filled with ice, through the evening and overnight, in the unairconditioned garage, in the heat of Texas summer, only to be pleasantly surprised with cold water in it, the next morning.
I absolutely love this bottle. If I really need to gripe, I guess I could wish for a CamelBak Insulated bottle with a larger capacity. CamelBak --- are you listening? :)