The most water-efficient models in our ratings use an average of 10 gallons of water, 75 percent less than older models.

https://www.consumerreports.org/washing-machines/best-eco-fr...

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.

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

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.

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?

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.

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.

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...

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

A possible future improvement could be delayed start that communicates with time of use metering or something, although this would have to be implemented in such a way that the software itself wouldn't turn the machine into a piece of junk in 3 short years (eg libre software).

I suspect there are also many sensor-based improvements that could give machines more intelligent processing, but anyone who has repaired appliances knows that BOM cost rules all. So those would seemingly rely on less time-based manifest-destiny "innovation" and more on designing machines with more value in the first place.

Certainly there not necessarily anything wrong with open source controller software but it’s no Panacea either.

And what surveillance? My heating system isn’t networked at all.

By surveillance I'm referring to what would pass for "remote notifications" of system status (after the possible bad sensor was detected). The IoTrash solution would be to backhaul your system's data to a surveillance cloud, require you to sign up for email spam, install a bespoke app that would spam you with useless notifications, faux-consent to a ridiculous anti-privacy contract, etc. Whereas in the libre world, user-focused incentives are allowed to define functionality and that notification could be a simple single email.

Making the point in general, in order for complex software to not be some terrible black box, it needs to expose its internal state to users who want to see it. Libre software tends to do that (as many users are developers), while non-libre software tends to lock all that up and thus severely limits reliability xor complexity.

Individuals are of course welcome to hack together what they want using Arduinos or whatever.

Again I very deliberately do not have a smart thermostat or other network connections to my heating so no surveillance is going on. I do have network-connected temperature sensor but it’s purely passive.

I too critically rely on heating. As system complexity increases with things like outside temperature sensors, I would much rather have visibility into their workings than not. In the middle of the night, that could be the difference between a quick ten minute diagnose and override, or waiting some hours for an emergency service call.

I had a similar failure with my hot water boiler, where an older solid state control failed such that when the circulator would kick on the burner would shut off. This allowed it to limp along heating, until a day when it was too cold out and I realized it wasn't keeping up.

re: libre software, my point isn't really about being able to audit the code, but rather about having a cross-device software-maintainer-maintained codebase that users choose to use.

FWIW another, probably better, way to mitigate this particular external temperature sensor failure mode would be a second larger control loop. When the indoor temperature is more than a few degrees below the setpoint (not as a result of a scheduled change), the furnace should be less-efficiently creating a larger amount of heat to get back up to the setpoint quicker. Which is funnily enough how people think most thermostats work when they ineffectively turn it up higher to get things warmer faster.

Though to be honest I agree with your point. A lot of the low hanging fruit for massive gains in efficiency are gone. It's like cars, going from 10 mpg to 20 mpg is a huge difference. Going from 50 mpg to 60 mpg is a much smaller difference.

But then the washer is stealing heat from your house? That seems questionable?

Seems like the right way to solve the problem is to provide hot water inlet, and that should provide it is whatever most efficient way you can?

(The water is either collected in a container or goes down a drain)

For modern top loading washers, the final temperature of the water is restricted by limiting the hot water let in, they don't have a heater.