This is just the amount of power the washing machine uses while it is on. You need to know the energy required to manufacture all of the components and the duty cycle, to know if it makes sense to replace an appliance for a more efficient one or not.

For example even if my phone charger were to get twice as efficient, it’s drawing very little power, given that it spends most of its time unplugged: it uses a fraction of a watt. That means that I would have to use it for an extremely long time to get near to the amount of energy used to manufacture a new one.

Washing machines pull considerable power and the power scales with the water usage: They use warm water, either from a tap or using a heating element. Heating water is energy intensive, and the hot water quite literally goes down the drain. Current machines use about 50liter per cycle, heating that from 10 to 30 degrees consumes around 1.2kWh, to 60 it’s ~3 kWh. Doubling the amount of water obviously doubles the energy needed. A machine for a small family may see around 100 cycles per year, so the savings are substantial.

This doesn’t take into account the savings in drinkable water which has most likely been through an energy-intensive process as well.

Yet your washing machine does not need drinkable water specifically (can use rainwater), and your stats do not mention the energy/resource cost of manufacturing and shipping a new washing machine.

If you have collective washing machines as a public service running 24/7, the tradeoff may be worth it, but as a general rule it's certainly not the case. Extracting and refining materials for industrial processes consumes millions and millions of m³ of water and a lot of energy.

Our perception as consumers is skewed because the price we pay for electricity/water makes it economically more affordable to us to get newer devices, but from a resource usage perspective, that's certainly not a good deal for the planet. If we paid water/electricity the price that big industries do, we wouldn't even think getting a new device was a reasonable choice.

Washing machines consist mainly of materials that are easily recycled and very economical to do so. Metals, mainly, in a large package. Pure copper in the motor. All of which can be recycled to build a new washing machine.

What stops a washing machine made in year 2010 from using same amount of water as one made in 2025? Was that water never needed at all?

Did we discover new phisics of washing? Do we have any reason to believe further improvement is possible?

This is a physical process, you can't have infinite improvement - there is a certain minimum amount of water required to dissolve detergent, and it can be easilly calculated.

They don't do much, does anyone have a real explanation without any handwaving?

I replaced my washing machine and dryer a year or two ago. I was pretty skeptical that a new set would make any difference, so I held off until it broke.

The new machines are better. I'm not an expert, but I think the biggest differences are: sensors to stop adding water when it isn't necessary, a really powerful spinner in the washer that dries the clothes better, powerful spinner in the dryer. Btw, my washing machine is top load, fwiw.

Oh, and to answer a different question: why didn't we have this stuff years ago? I think, no one cared enough to do it.

Have you watched the cycle of a modern front loader versus an old top loader?

The old top loader basically filled up a big tub with hot water and sloshed it around a bit.

Modern front loaders just incrementally add the amount of water needed as determined by weight. Presumably wouldn’t have worked nearly as well with the available detergents of 50 years ago.

First, we should be talking about the next 20 years - after all we are talking about a law we will introduce today, not in the past, and noone it talking about appliances lasting a century.

Secondly, while I never used a top loader, from everything I've read, they are worse in every dimention, so the comparison seems inappropriate - you are introducing extra variables.

Also I am not clear why 'incrementally adding water' was not possible previously, People built a 'smart' toaster 70 years ago, that could sence how cooked your bread is, and it was purely mechanical:

https://www.theverge.com/22801890/sunbeam-radiant-control-to...

Top loaders are basically an automated version of doing laundry but by hand. A 40-50 year old top loader which is probably what mine would have been today if it had kept working is much much simpler in many respects than a modern front loader. The spin cycle and it’s control is very different. I doubt you could build a modern washing machine with 1970 technology even if you knew what the end goal should be. And you need the right detergent too.

Added: And toasters still do a crap job of figuring out done-ness.

These are generally firmware updates, no? One could imagine the same chassis, hardware and drive system with only a few modifications to sensors and the control hardware (perhaps even just an update to the microcontroller's firmware) achieving the same output.

And front loaders at least spin out more water so drying is more efficient. I suspect there’s less of a difference with dryers.