60%? is a very optimistic number, and even if granted, does nit address the horrible reliabilty problems with heat pumps, which change the economics considerably.
Heat pumps are noisy, and physicaly intrusive uggly wall lumps inside, and create a clutter outside.
Well built passive solar creates a living environment that needs no heat source, is orders of magnitude more reliable in all conditions, while bieng invisible to all but the most observant.An added benifit is that a passive solar house is also acousticaly insulated, and therefor
much nicer in a noisy, urban environment, near roads, etc.
Financialy, the costs of building a passive house
are not excessive, and once established, represent transferable value, while .... :)....insulating you from energy market fluctuations.
You realize that heat pumps are just ACs that can just run in reverse? Most American households already have central air. They'd just swap to a reversible AC ("heat pump") when they need to replace their AC.
Mini-splits are commonly used for retrofits because they're much cheaper than installing or repairing leaky ducting. Incorrectly sized or leaky ducts lead to poor efficiency, comfort, and air quality, regardless of heat source.
"Well built passive solar" is all well and good for the tiny percentage of Americans that get newly built passive homes. The rest of us need solutions as well. The idea that building a new home is more economical than $1000 per ton of capacity for heat pumps off Amazon is hardly worth addressing.
