I ONLY diffuse on high heat, high fan -- it doesn't take that long that way. I move the dryer w/diffuser around trying not to mess up the curl pattern -- mine is dry in about 10 min., well I don't dry all the way - probably to about 75% and my hair is just below ear length and fine/med porosity but I have a lot of hair. I read somewhere you are better off drying hot, high fan for shorter amounts than low heat, low fan for longer periods. I don't know -- just works for me.