A 10-12 year old AC is not old. I am not sure I believe the tech's diagnosis. Did you get a second opinion?

I am just a homeowner so i can't help much. What do you mean by a "good split"? Does that mean the ductwork isn't right? If it's not right then a new system won't make it right. If you fix this "split" issue maybe your system will keep up? OR is split just numbers.

I assume it used to work?

The guys here will want all the specifics on your home, size, floors, location, basement,and more about your current system (models)

I think you are at that age where you can go either way. If you move in 5 years you will have an aged system that buyers will be scared of. If you replace it now at least you will reap the benefit of higher efficiency, better cooling and dependability and warranty. If you have low eff furnace you might want to consider the whole package so get prices for ac alone and whole hvac.

I get my new stuff tomorrow. We haven't had problems really, though it did struggle with those 95 degree days, but we did get it down to about 78 so not as bad as you. Sometimes I think it still works more than it used to even in the 80's. Ours just had it's 17th season. Many neighbors with the same system have had problems that called for replacement.We decided to just do it without the emergency feeling that could happen in the summer. Looking forward to the 10 yr part and labor warranty!

Thanks for the responses:

Mike home: No, as the heat and humidity had decreased enough that my house was plenty cool inside by the time I got people out. I delayed a bit as I was initially blaming hot flashes. The techs can't really diagnose unless the problem is occurring, but the fact that it was working fine at 90 to 95 made one of the installation contractors question it. He thinks I should wait until next summer so that he can test.

I am not having any problems with the heat

Cindywhitall: I'm not exactly sure, but the split has to do with air or air pressure going in and out of the system. Nothing to do with the ductwork. My system is 80% efficient, so unless it's broke, I doubt that I will recoup savings within that time. Unless having a dual fuel system will save a ton, I am in South Carolina. 1928 brick bungalow, old windows with storms. I posted all of the info earlier and will re list all of the details if anyone sees a value in getting a new system. A couple of issues are that the electrical from the meter needs to be in conduit and the ductwork isn't the most efficient as it was added on in the original furnace duct (changes would depend on the type of system selected).

Anyone else want to jump in?

""The return and supply did not have a good split. The pressures were good, however he could not add refrigerant due to the head pressure rising too much. ""

If the pressures where good why would you want to add refrigerant???

Get a second opinion from another contractor.... a good one will be able to diagnose any time of the year.