"These installers are reaching astounding levels of efficiency by taking extra care to design low-temperature heating systems that warm rooms without using excess energy."

I'd at first really like to find a plumber that does not look at me as if I was an alien creeping out of mud when I tellem that if the central gas heater breaks down completely I want a heat pump. There's really hard conservativism in that business here.

"New generation of engineers" is a bit cringe. The old generation knew thermodynamics pretty damn well. All that's changed is they're using R290 refrigerants and variable speed compressors now, but those don't change anything from a physics perspective. COP is fun but it's not even the right metric to use from a policy perspective, just like MPG. And despite being unitless, COP suffers from the same exagerative effect as MPG numbers. What matters is the carbon associated with delivering BTUs to a home, so here you can have the ridiculous case of delivering more BTUs at a higher carbon cost achieving a higher SCOP than the same exact heat pump delivering fewer BTUs at a lower total carbon cost achieving a lower SCOP for a better insulated home, and the person with the higher SCOP bragging about it like a clown. At least when the government tests COP it's a standardized test so you can actually compared equipment (somewhat).

Regardless, nerds gonna nerd and no harm done (and I also track real time energy use of my heat pump, so I consider myself a nerd).

Be great if I could afford one though

I saw 5 for air-air and was impressed. Then I see SCOP? Oh please. Why not change the scale again to make sure nobody knows what a good value is. Just like SEER on an air conditioner.

SCOP varies depending on environmental conditions!

Real COP or go home IMO. Watts out/watts in, no fudging numbers to confuse consumers again.

I'm just surprised there's no "AI heat pumps" yet.

Now that's something the world is really needed. (/s)

Nice read

"Heat pump" is just the latest buzz word. If you look up how they work its literally just a regular air conditioner with a switch to reverse the air flow.

Compressing refrigerant, allowing it to absorb thermal energy from inside the house, pumping that refrigerant to an outside coil where it releases that energy, then compressing again. This is air conditioning.

Not saying it's not useful or whatever. But it's not some incredible new technology. You could accomplish the same functionality by installing your window unit backwards.

Define efficient.