Eco settings can be found on many washing machines and dishwashers. Washing cycles are a mix of three things, temperature, time and water. With eco modes, the machine is set to use less water and a lower temperature - or a combination of the two, cooler cycles may take longer to finish but will use less energy in the process.
According to Curry’s 90% of a washing machines energy comes from heating up the water so using an eco setting can make a difference, and using a lower temperature setting uses between 35-59% less energy than a hot wash.
According to which, using an energy saving or eco setting on a dishwasher can use 20-40% less water and energy than automatic or normal settings.
Remember- This information is just a guide. No two washing machines cycles are the same, variables include drum size, quality of machine, energy rating, amount of clothes in the machine, type of clothes etc when looking at your machine always check out the energy rating sticker and refer to the manufacturers manual for specific information.