The humble, hard-working dishwasher can be the most contentious appliance in your kitchen. It's the source of bickering fights over the right way to stack plates, bowls, mugs, pots and pans. Agnes Bouchier-Hayes from Technological University of the Shannon joined the Today With Claire Byrne show on RTÉ Radio 1 to talk about all things dishwasher-related. (This piece includes excerpts from the conversation which have been edited for length and clarity - you can hear the discussion in full above).

First things first, you don't have to rinse dishes. "You can rinse them, but what you're doing there is you're actually using water that is unnecessary", points out Bouchier-Hayes. "I would advise always scrape dishes. You don't want debris going in, but they still have the technology to deal with that. They're all designed quite specifically to remove all of that dirt so rinsing isn't necessary.

Are you one of those who ignore the warning lights about adding rinse aid and salt?

Then, there's the matter of the eco wash cycle which seems to go on forever. "It's kind of counterintuitive because you don't expect something that takes longer because the eco cycles on most dishwashers take much longer than the normal cycle. But the eco aspect comes with the amount of water that they use. They use less water. Equally, the energy that a dishwasher will use is mainly concentrated on heating the water, which eco cycles run at a lower temperature. Even though it's running for longer, you are saving on the electricity. The general advice is to run the eco as often as possible. If you have time, you should run the eco cycle.

The dishwasher itself also needs a good clean annually. "You do have to clean your machine", says Bouchier-Hayes. "If you use your machine and you scrape and rinse, you should be only having to clean your machine once a year. If you've removed the bits of carrots, the bits of onions, if you've scraped that off, that debris really shouldn't be there and everything else should be caught in the filter.

"Now, there's a couple of different ways that you can clean your machine. Your filter's at the bottom of the tub of your dishwasher, and you can remove that and you'd use a soft cloth to just clean that out. Don't use a wire brush or anything like that, but just use a soft cloth and sponge to clean that.

As for the cutlery, don't be a spoon

"If you're getting a smell or if you want to clean your machine a little bit more, you can run a cycle through with a dishwasher tablet specifically for cleaning the machine. Equally, you could get a measuring jug, put some distilled vinegar into it and let the machine run at a hot wash, and that will clean the inside of it and then you can put some bicarb soda, because sometimes you can get a little pong from them."

Are you one of those who ignore the warning lights about adding rinse aid and salt? Well, you have to do it, says Bouchier-Hayes. "It helps your machine run more efficiently. A lot of the detergent tabs and pods that we use now have both of these present in it, but not to the level that you require. The salt is there to help soften the water because softened water will help your dishes to clean more efficiently. When the light goes on, put the bit of salt in. It does help. It keeps your machine running more efficiently and the rinse aid will help everything coming out come out far, far more shiny and helps the drying."

So, the main event: how you should you load your dishwasher? "The sage advice at the moment is, fill it to capacity, not over fill it, fill it to capacity so that everything can be washed and allow the water to run through and run it on the eco cycle", says Bouchier-Hayes. "You'll use six to 9.5 liters of water as opposed to maybe your sink's 18 litres of water."

As for the cutlery, don't be a spoon. "People wonder should they put the knife down with the handle up. You should always put the handle down so that the utensil part that has been used and that has been in your mouth is getting the benefit of the water and getting cleaned first so putting the handles down is the first thing. If you have silverware, proper silver, you wouldn't put those in next to stainless steel. Rinse aid will help as well, to make sure they're shiny when they're coming out. If you have spoons stuck together, that's not going to work, because the water won't be able to get through it, so make sure the water can get around the various bits and pieces that are in there."