Jul 29, 2017 · Consider the figure above and example, the cooling load is calculated to be approx. 2.5 tons. The A/C system selected to cool this space is specified as a 2.5-ton system with 230VAC input and R.L. (Running Load) of 9 amps. Most manufactures size residential A/C systems in 0.5 ton increments so this works out very well at 2.5 tons.