Is it better to wash your dishes by hand or use a dishwasher? This question from listener Eve has got to be among the most hotly contested debates out there. She wants to know which method uses more water and which is more energy efficient. To find out, we speak to a man who's spent decades studying the differences - Professor Rainer Stamminger from the University of Bonn in Germany. Eve also wants to know about the eco settings on dishwashers: how can they save money if they take so much longer? And should you pre-rinse before putting things in?! In short, does the evidence around dishwashers stack up (sorry!) Greg will be finding out. PRESENTER: Greg Foot PRODUCER: Simon Hoban