I do use the energy rating info for a fridge or fridge/freezer, the annual usage divided by 50 is what I expect it to use in a week, they are never as efficient as claimed, so divide by 50 not 52 and about right.
However I tried with washing machine and the energy rating info is about as much good as chocolate fire guard. Every wash is different as the machine weighs the load, the fast you no longer get a hot fill except for specials designed for narrow boats, means in a home where the water is heated with solar energy that energy can't be used by the washing machine.
What is important is things like the drying cycle temperature, and how the moisture is removed from the air, I know my washer drier is very wasteful, it uses cold water to condense moisture from the air and is also too hot, so I use a independent dryer. Again my laundry room is not heated, or cooled, so a pipe out of the open window from the drier works well, but in the last house had a hole in the wall with the pipe blowing air outside, but the replacement air came from inside the house, not as with this house through the open window.
So all the air used has been heated, and is also more humid that cold air to start with, so exactly the same dryer, is far more efficient in this house to last house. Also in the last house there was a problem sucking air from the house, as we had open flues, in real terms the house had so many vents a depression was unlikely, however as we fit double glazed windows and better sealed doors houses do become better sealed.
I remember 1970's when we got married, we had a twin tub washing machine, and on washing day the kitchen was full of cloths, we started with the clean cloths and progressed to most soiled, and each group would use the same water, the machine would be filled a few times so on final rinse the water looked reasonably clean, but energy wise it must have been quite efficient in the use of water, and power, but rather inefficient in its use of labour, my poor wife was washing all day, and the car had to be parked in the drive as car port used to dry the cloths, must admit the car port between the houses was the best drying tool ever, the wind was directed by the houses through the car port, so loads of fresh drying air, if it rained the cloths did not get wet, and birds did not frequent the car port so no need to rewash due to bird lime.
So what I am saying the energy used to wash depends on the home, how humid the air is, how the cloths are aired, etc. We have a system boiler so a cylinder and cold water tank so have an airing cupboard, last house had instant hot water boiler so no airing cupboard.
So how can any washing machine be rated when homes are so different?
