3.5t westing house outside 6 monhs old/Payne 3T atic 7 years old

[mojeime]

I have 3.5t westing house unit outside of the house,6 monhs old and Payne 3T unit on the atic 7 years old.
The temperature in the house is 82 and outside in the shade 92. Inslutaion is pretty OK.

I am thinking about replacing atic unit. Is needed to replace whole unit or only parts for cooling.

I do not know anything about A/C.

Please advice.
Thank you

[beenthere]

Whole unit. And it must be a match to the OD unit.
Why was the OD units size increased.

Can your ductwork handle the extra that the bigger OD unit needs.

[mojeime]

I planned in the future to have bigger unit on atic.
The house has about 1600 sqf.

[beenthere]

Tends to be bad for the outdoor unit when its sized larger then the indoor.
Also tends to void warranty on the compressor.

You may not have a 3.5 ton outdoor that is only providing you with the capacity of a 2.75 ton because of that match up.

Once the proper matching indoor unit is installed, and the ductwork correction are made for it. It will cool faster.

Oversized systems don't remove humidity to well. So you may still end up between a rock and a hard place. It may cool it faster. But you could end up having to set it lower to feel as comfortable. Costing you more in electric.