The entire 10 paragraph article is based around a single tweet from Musk and doesn't explain a single thing about how the heat pump in the headline works.

You could buy a mini split heat pump from mitsubishi today. Five units of heat for every one of electricity. Rock solid reliability. I'm not sure it needs reinventing. What it needs is a better service industry so you can get them installed and maintained cheaply. Cheap installation, maintenance and repairs of the heat pumps we already have, that would change the world.

You _should_ think about heat pumps for HVAC in your home, especially if it's well-insulated (if not, think about insulation and heat pumps). But you should buy one made by Mitsubishi or Fujitsu, which are already amazing.

Only in certain climates though. Heat pumps typically perform poorly in colder climates where it's difficult to extract heat from low ambient outdoor temperatures. I work in HVAC and we almost never use them here in Denver because you can't get enough heat out of them when you need it the most.

Mitsubishi and Fujitsu both have models that are rated efficient down to -15F now, with anecdotal reports they can handle -25F.

They can be tough to get in some areas though, if you want to use a local supplier. I bought the best modern model available from HVAC companies in my area, and it resorts to backup electrical heat around 15F. But that's still fine for my climate (northeast US).

Can't you also (in new construction or remodels and not in permafrost areas) bury a heat exchanger underground?

Yes, they call this "geothermal" (although it's not like geothermal power generation). You can also use lakes and large ponds rather than burying it.

I looked into it last year. The main problem is cost (in getting into the ground) and expertise. In my area at least, there are dozens of reasonably solid residential HVAC companies with extensive traditional heat pump experience, and zero with extensive geothermal experience.

Flagged because all this article is, is some shallow quotes from Elon's Twitter and statements like "people are speculating how it works!" There is no new information nor interesting analysis.

I really don’t understand quite what’s going on here - most home heating and cooling in my country has used heat pumps for years, isn’t that the case in the US?

In Canada we have really cold weather and heat pumps are used but only down to between -5C to -10C depending on the efficiency of your pump. If I tried to run my heat pump in really cold weather it would just never reach the desired temperature.

One option is to use a ground-source heat pump in that kind of situation, if you have enough land to dig or drill to install the exchanger pipes. Most places in Australia where I live are able to just use air source but I've seen ground source ones in Europe.

Some parts. But for a car sold in all 50 states a general heat pump isn't going to work.

Some areas can get down to -20F, even -40F in the winter and this is major metropolitan cities.

Perhaps this is a new type of heat pump or it sources heat waste energy within the car itself.

Doesn't the Nissan Leaf use a heat pump as well?

A lot of EV use a heat pump. Some old model had a petrol heater, like the EV version of the Peugeot 106