In the midwest a geothermal heat pump would work wonderfully.
Also, they are designed to run constantly in order to maintain the set temperature -- it's not like a natural gas fired furnace where it quickly reaches the set point.
Additionally, there are multiple types of restrictions on where geothermal pumps can be installed, and navigating this can add to costs.
I don't see it as a one size fits all solution, there are far too many people for whom the household/company math doesn't add up. However, I agree we should be doing fair comparison against other renewable-friendly options for all new construction. I'm sure heat pumps could win out in a great many situations, and we should use them where they do.
Note that a heat pump cooling a building is essentially the same as an air conditioner. So it's more a matter of how efficient the air conditioner you're replacing is. Cooling a house is much easier than heating, because the temperature differences are lower. In your example, cooling 95 F to 70 F is a 25 F difference, while heating 20 F to 70 F is a 50 F difference. The world record for heat is about 135 F, which is the same difference from 70 F as 5 F, a completely normal winter temperature in much of the world.
GP's comment was about the tech, though, and not the cost of said tech.
It's absolutely not a perfect solution for all heating needs across the globe, the the technology is far better than GP is suggesting.
My main concern is the overall long term efficiency & affordability of renewable-friendly solutions, because competitiveness in those areas is what will lead to mass adoption. The point I was hewing toward is that I feel the heat pump advocates and providers need to make it more clear which situations are best suited for that solution and which are not, because it would benefit everyone.
Habits are hard to break, though, and there's not much value (if any) of lowering the set-point at night during the winter months. People still do it, though, and then the unit is working overtime in the morning to reach the desired set point.
I'm glad that you're happy with your setup!
Personally, for my home and climate in the area, I disabled aux heat entirely, unless the temperature is below 0f outside, or if it hasn't reached the set point within 2 hours. Recently had some cold weather and these settings worked well for my home.
I'm using an Ecobee, configurations will vary per thermostat. The big settings for me were using manual staging to configure the temperatures to engage aux, temps to lock it out, etc.
Not all heat pumps are variable-speed like you describe. My own home, built in 2000, has a single-speed heat pump that kicks on 100% or off, like a regular old AC unit.
Mine is a variable speed unit, but that's not the function that I'm talking about.
