I have a 14 yr old 10 SEER 5 ton Trane AC unit with a single speed blower. I have been looking into replacing the unit with a more efficient model. I have been looking at the 21-23 SEER IQ drive units but they only come up to 4 tons. An AC company did a heat analysis survey on my house to determine AC size and he said it is saying that I need a 4 ton system. I have had a few AC companies give me a quote and many of them say they would not recommend dropping a Ton. I live in a 2600 SqFt 2 story house in South Florida and I don't want to have an undersized system.
I have also looked at the EER rating on this system and it shows 12.6 @ nominal capacity - 95 deg outdoor dry bulb / 80 deg indoor at 51% humidity.
I also looked at a 5 ton 16 SEER Amana that shows up to 12.5 EER when matched with a certain blower / furnace.
Now for my questions; If the 4 ton 21 SEER unit is running much more than the 5 ton 16 SEER unit is there going to be a big difference in energy efficiency given the fact that the EER values are so close? Would it be safer to go with a 5 ton, which is also about $900 cheaper than the 4 ton IQ drive? Should I listen to the AC people giving me quotes or the heat load analysis sheet that says I will be fine with a 4 ton?