I've never really done anything to my hair..never dyed or thermally straightened or any of that. I usually air dry but I'm considering getting a hairdryer with a diffuser that has cold and hot setting... Does cool air still work? I'd like to do something totally undamaging, which I assume cool air is?

My hair is layered but the layers are getting grown out and aren't much shorter than the longest parts in the back.. once I get it the length I want (bra strap length) I plan on getting some layers, so maybe I'll see more wave then.

Thanks for the input!