You will find a comment from me on what is missing from the story.
I have not yet followed this link:
https://www.youtube.com/watch?v=OcwIz6heDss
The above is WELL worth watching! About 1.5 hours. A very significant "take away" is that southern air conditioners are "over sized" because the cooling demand is much greater than the heat demand. The charts indicate that most of our air conditioners could also serve as heaters for outside temperatures down around 20-30 deg F. We would be far better off if the air conditioners were sold as "heat pumps", able to produce needed heat under most conditions. Instead, the "low cost path" has us burning natural gas or electricity at all times that heat is needed. Another take away might be that heat pump heating becomes more expensive than petroleum burning or electric resistive heating at some point of temperature. On average, the heat pump is almost certainly cheaper due to the few hours that are spent at those inefficient hours. In Caribou Maine, the cross over points are -2 and -9 deg (for propane and natural gas, respectively) both give great heat pump savings over entire winter because few hours are spent below those cross over points. In Texas, an air conditioner that works for heat also should serve as a heat source under most to all conditions; that is, in part, because our air conditioners must be sized (over sized) for our hot summers. Another take way might mean that Menkes should run their heat pump more since "always on" instead of daily thermostat adjustments is cheaper to operate. They seem not to discuss the value of dehumidifying with a heat pump as I have recently discussed.
Take away from Q&A session: A heat pump gives better "bang for buck" than insulation and air sealing. That is in opposition to "conventional wisdom". Recommendation is do heat pump first, then insulation/filtration remedies. At least, that is the case in Maine.
Advertised numbers/ratings indicate that the smaller mini spits are more efficient than the larger units. That was a factor in my selection of units. Those numbers/ratings may or may not be accurate.
4/16/23
Here is an excellent blog post case study of conversion to heat pumps:
Note that the heat pump installed was a low-end, low efficiency, unit that is
"ducted" rather than a mini-split. The overall efficiency rating (for both heat and cool) is SEER 16. My Diamond units are in the range of SEER 22-25. I don't know the heating efficiency rating on my units. The Cleveland study unit is HSPF 10. Note that my installation is very much "zoned"; the ducted units do not lend themselves to zoning. "Zoning" meaning using heat/cooling only in occupied space. My house has a small (9k BTU/Hr) in the bedroom; it is used only at night. The two daytime living area units (9k and 18k) are used either one at a time or both and rarely at night.
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