Hot fill
Hot fills are basicly obsolete as well.
Any modern dishwasher barely fills with 3-4l, a washer with maybe 10-15l for an average main wash.
Between fills there often is 15min or more.
So, with a dishwasher, you often don't get any benefit at all (especially with DW that have a heat recovery system) and with a washer, you might get some warm water, but you waste a lot of heat in form of the hot water in the pipes.
While it is true that the production of electricity is still more impactfull in terms of the enviroment then directly using the the resources, that will change over the next few years.
There are a few verry narrow use cases where hot fills do make sense, and for those machines are still avaible.
But given that the benefits can go negativ quite easily, just going cold fill only makes things much easier.
Solar water heating just isn't verry practical for everybody.
Here in Germany most solar heating systems barely allow for 50C hot water temps in summer, thus booster heating is always required.
Our house back home has enough correctly orianted roof area for 2 collectors, for a (then) 5+ person household and 200 square metere contiously heated area.
With maybe effectivly 100 sunny days and an install that would have to go from the roof the basement (12m, at least), an install like that only becomes viable after decades.
You can't just make the most efficent thing mandatory. That would make the already insane real estate prices go even more extreme.
You have to find a good balance between efficency and economy (2 verry different things, by the way).
A basic ventilation system is about 10k€ for a first install on a new build house and has a predicted lifespan of at least the same as your heating system, often twice that, and saves between 25-50% of heating cost, depending on house.
They are mandatory for all new buildings.
Why all new buildings only?
Adding such a system to an existent, maybe 30-40 year old house, plus sealing the house to the point where the system actually has any effect is about 3 times the install cost.
Hot fills are basicly obsolete as well.
Any modern dishwasher barely fills with 3-4l, a washer with maybe 10-15l for an average main wash.
Between fills there often is 15min or more.
So, with a dishwasher, you often don't get any benefit at all (especially with DW that have a heat recovery system) and with a washer, you might get some warm water, but you waste a lot of heat in form of the hot water in the pipes.
While it is true that the production of electricity is still more impactfull in terms of the enviroment then directly using the the resources, that will change over the next few years.
There are a few verry narrow use cases where hot fills do make sense, and for those machines are still avaible.
But given that the benefits can go negativ quite easily, just going cold fill only makes things much easier.
Solar water heating just isn't verry practical for everybody.
Here in Germany most solar heating systems barely allow for 50C hot water temps in summer, thus booster heating is always required.
Our house back home has enough correctly orianted roof area for 2 collectors, for a (then) 5+ person household and 200 square metere contiously heated area.
With maybe effectivly 100 sunny days and an install that would have to go from the roof the basement (12m, at least), an install like that only becomes viable after decades.
You can't just make the most efficent thing mandatory. That would make the already insane real estate prices go even more extreme.
You have to find a good balance between efficency and economy (2 verry different things, by the way).
A basic ventilation system is about 10k€ for a first install on a new build house and has a predicted lifespan of at least the same as your heating system, often twice that, and saves between 25-50% of heating cost, depending on house.
They are mandatory for all new buildings.
Why all new buildings only?
Adding such a system to an existent, maybe 30-40 year old house, plus sealing the house to the point where the system actually has any effect is about 3 times the install cost.