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I currently have installed in my home an AC system that features a 3 ton, 12 SEER condensing unit, a 3 ton fan/coil unit w/ piston metering device. No heat (radiant floors). The duct system is engineered and balanced. AHU and ductwork are in an unconditioned attic in southern Indiana. We can experience dew points of 75°F plus for weeks at a time. Normal would be low 70s. I installed the system in 1999. It has run and cooled my home faithfully with no problems other than one rodent gnawing incident and one replaced contactor in these 19 years.
I am set to retire this equipment and replace with new. The current system has always performed as an oversized system would. We went with rule of thumb selecting it. Two things I never liked about this system were the fan speed, I'm guessing around 1300 CFM, and lack of dehumidification. I'm downsizing and going with multiple fan speeds and a TXV.
Will simply applying these measures get me to where I want to be?