Have you ever looked at how A/C systems are designed? The engineers determine the parameters on a “design day” by calculating the “sensible load” (heat enterin

Have you ever looked at how A/C systems are designed? The engineers determine the parameters on a “design day” by calculating the “sensible load” (heat entering the space from outside + sunlight + people + equipment, etc) and the “latent load” (rate at which water vapor enters the air from ventilation, leakage, people, kitchens, showers, etc, times the heat of vaporization of water to get it in units of heat), and then design an air conditioner that will remove heat and vapor, in the corresponding amounts and ratio, at steady state at the indoor temperature and humidity they choose, under the design conditions. Then they throw a thermostat in so the temperature is under closed-loop control. Of course, this means that the humidity is under open-loop control based on the wild guess they made — YOLO! And there is absolutely no effort made, even if the calculation is right, to get the system to converge to design conditions quickly. Add people to an office with lots of windows and sunlight coming through those windows, and the sensible to latent load ratio changes, and there goes any semblance of humidity control. If you’re in a hot, dry climate, it may be impossible to get the parameters right under any conditions with ordinary air conditioners. Never mind that the installer probably messes up, resulting in leaky ducts, and the sign of the resulting massive error isn’t even well determined if you can’t predict which duct leaks the most. I’m aware of exactly one vendor of A/C equipment that will attempt to adjust the coil temperature to control humidity based on actual measurements. Mitsubishi has a “dry” mode that is very much not closed-loop and is barely documented. Good luck. At least in humid climates, it’s possible to install separate systems for cooling and dehumidification.