My electric washing machine has an express wash button (they seem a common feature) that reduces the washing time by a lot. My first thought would be that using it would save energy because of the much shorter time, but I'm guessing it has to do extra work to wash in a shorter time (faster spins?), so I could be wrong.
I've not measured the time difference, or looked at an energy meter because I'd like to know if there's a general principle I can apply.