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.
"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.
I live in a progressive state in the US and currently renovating a house. Holy crap they all fight me tooth and nail telling me what a horrible idea they are. Nothing but problems, always break, oh my goodness what if the power goes out, the grid cannot handle the load so don't do it. These old timers need to go away.
During last winter gas heater servicing I told the plumber to set the unit to 50°C heating water output so I could check if the heaters would get warm enough with a heat pump. 1,5 hours of discussion about old buildings and heat pumps resulted till he complied.
It was just a test setup that could be reverted any time.
"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).
What really matters is the wattage needed to cool the space. That's really it. The less energy used, the less the strain on the grid, or the less solar capacity needed.
Wattage is power, not energy. But I still generally prefer carbon as a metric because that's the climate issue, so by focusing on it directly we can make more informed decisions. It also incorporates time of day/seasonal (peak) impacts implicitly, which also have profound effects on the grid, more than total energy used. The essence of our comments is the same though.
Not sure where you're located, but there are often significant incentives for heat pumps. If you're US and low/moderate income, there are big programs ramping up via the IRA that will cover a large percentage of the costs, assuming you're not in a total brain dead state.