> 1 - drier air feels cooler, and has other advantages (reduced condensation on surfaces, etc). This is the cargo cult problem. When it’s too humid, dry air fe

> 1 - drier air feels cooler, and has other advantages (reduced condensation on surfaces, etc). This is the cargo cult problem. When it’s too humid, dry air feels better. So HVAC engineers pick a nominal coil temperature based on some design climate and use it everywhere. Dryer does not feel better in hot, dry places. > 2 - it’s more efficient for them to do so, considering heat exchanger surface area, the phase change temperature of the refrigerant, etc. I have not gone through all the math, but I’m willing to bet that this follows from #1. Engineers picked a coil temperature and designed from there. There are multiple refrigerants on the market, the operating pressure of a system can be controlled at least a little bit, and it’s even possible to operate the coil warmer than the refrigerant with no fundamental change in COP. (Hydronic systems do the latter regularly by recirculating some of their working fluid.) As far as I can tell, there is no market for an air conditioner with better humidity control because no one has created a market — everyone expects that air conditioned air is unpleasant, and no one has marketed their superior system well. (Lots of people in very humid climates think that comfortable air conditioned air is too cold — they have to set thermostats to 70 or even lower to be comfortable. This is because of inadequate dehumidification. Lots of people in hot, dry climates think that air conditioned air is too dry. These people aren’t wrong.)