I hope the scientific community can settle an argument between myself and my father...

I often wash my dishes in cold water because it takes too long for the water to run warm (and I'm lazy). My dad insists that you have to wash up in warm water to dissolve the grease, but I say that the temperature of the water has no effect because it's the detergent that emulsifies the grease and does the actual "getting clean" bit.

Who is right?