I have a 20 yr old trane 5 ton split system with two 2.5 ton condensors and one 5 ton air handler. Right now the evaporator that goes with the newer condenser is covered with ice. The tech who answered the call said that if I were to get a new system it would be two separate 2.5 ton units each with their own air handler and duct work. Do you think that a single 5 ton system would be better? And have you ever heard of the configuration I have now? On my current system the 2nd system lights off when there is a 5 degree difference between the thermostat setting and the indor temp, is that a very effective method of cooling a house? I live in NE Florida in a single story brick house with 3000sqft. I would appreciate any responses to my questions.