You are going to need to provide a source for your claim that cooling is less efficient than heating. AFAIK from my days as a mechanical engineer, heating from an electric source is ~95% efficient and cooling is ~30% efficient...
But the reason cooling is cheaper is the temperature differential. AZ might get to, say, 110°F peak (and far cooler at night), for a temp delta of 35°F while the Midwest will stay below 20°F for months, and even colder at night, for a temp differential no better than 50°F during the day and 60°F at night.
In cooling mode they provide a source of fresh-distilled water! It always bothered me when air conditioners just dump that water down the sanitary drain instead of pumping it in a garden or misting it on the outside coils.
Fresh is not the word I would use for condensate. Try drinking some of you disagree :). It's corrosive for metal,{EDIT: maybe I just have that confused, see replies} which is why it usually doesn't find a purpose, but you could run it to plants. I have a window A/C which uses it for cooling the outside coils though.
Legionella is a concern though.
https://www.environmentalleader.com/2013/01/air-conditioning...
that's thermodynamically impossible. @dktoao, being a mechanical engineer, surely understands this, and made a statement that is different, and more plausible.
COP is a ratio of change in energy (e.g., temperature) produced against a common benchmark (running electricity through a resistive element, for example). that's how it can be greater than 100%. absolute efficiency (what @dktoao offered) compares against a 100% conversion of energy from one form (or place) to another. in this case, you cannot beat 100% (or generally get super close) due to the 2nd law of thermo.
And, "efficiency" doesn't matter. COP does. COP is what is reflected on your electrical bills.
If I am in my house, use 1000 W of electricity, get 3000 W of heating, that is what is important. No shit the extra heat comes from the environment. It doesn't matter unless you live within a house completely located inside an artificial climate-controlled area, which applies to... none. No houses.
Considering the temperature extremes that southern US versus northern US housing experiences over the entire year, it's probably easier to keep the southern house around 21C than the northern one.
https://zeroenergyproject.org/warmer-climate-construction-de...
https://www.eia.gov/consumption/residential/reports/2009/sta...
Sure, but in a cool climate you need much less cooling to be comfortable than you need heating in even a neutral climate.