Is it better to undersize or oversize AC?

Is it better to undersize or oversize AC, it is slightly better to undersize by half ton than to oversize by half ton, but best is to size exactly correctly via Manual J load calculation, as both extremes cause problems. Undersized AC means unit too small, for example 2-ton for home needing 3-ton, consequences are runs continuously on hottest days and may not reach set temperature of 75 degrees when outdoor is 100 degrees, staying at 78 to 80 degrees, but it will dehumidify very well because long run times remove lots of humidity, keeping indoor humidity at 45 to 50 percent that feels comfortable, and uses less energy per hour though runs longer. Oversized AC means unit too big, for example 4-ton for home needing 3-ton, consequences are cools air quickly but short cycles in 5 to 10 minutes, does not remove humidity, leaves home clammy at 60 to 70 percent humidity, causes more wear from frequent starts and higher bills, and creates uneven temperatures. HVAC pros say if you must choose between slight undersize or oversize, choose slight undersize or exact size with variable speed that can ramp up. Modern variable speed AC like Trane XV20i can operate from 30 to 100 percent capacity, so slight oversizing is less harmful as it can run low most time. For single stage AC, undersizing by 0.5 ton is better than oversizing by 0.5 ton for comfort and humidity. Always get Manual J calculation for exact size.