I heard somewhere that thc dissolves into the water, but to a lesser degree when put through warm water... I have no evidence to back this up, maybe it is more important when using a vap-bowl in a glass on glass bong....Im not sure, just wondering what you've been able to find out using scientific data. ( i know that water can hold more air when it is cold ie. putting soda in the fridge, but i don't know if this principle carries through for bongs...)
oh well, both ways get you high