That's true. Strictly speaking a heat pump doesn't need a resistive heating element, but I've never heard of units not containing that feature. After all it's dirt cheap and enables the reliability, we're discussing here.

Real question is does it prevent freezing? Like 100%. After all, the human body is quite resilient … above freezing.

I am thinking in Nome, Alaska where such heat pump could prove its versatility as an anti-freezing component of living quarters or even maintenance shed.

Humans can put on clothing and be fine in very cold temperatures. However pipes cannot 1C is a hard minimum safe temperature, once it gets colder than that you risk pipes breaking.

Perhaps, instead of spreading FUD, it would be worthwhile to mention these "certain temperatures", so that people can make an educated decision of whether it applies to them at all.

I'm looking at the datasheet for my Fujitsu system and it is specified to work down to -25°C.

Does it lose efficiency when it's cold outside? Sure. But guess what, it's still more effective than resistive heating! I am starting from a SCOP of 4.89.

The UNIT is specified to work down to -25. The SYSTEM includes the building it is installed in: the local climate, the size and heat loss of the building, how the install was done, and likely some other factors I'm not aware of. If you get less heat from the unit than you lose via other means the system isn't working even though it is delivering heat.

Perhaps you should have read my comments more carefully. There is absolutely zero "FUD" in any of them. I'm just pointing out facts. The primary fact is that you don't need historical data from heat pump installations to know if they'll be efficient in a given area or not.

They're devices. They're engineered. They have specifications. The specifications have implications as to how they will function in a given environment.

I'm not here to sell heat pumps or to make you feel good about your past purchases. Are you?