With a single non zoned air conditioning unit you have to keep every area cool at the same time.
Upstairs airconditioning unit separate in attic.
The installation only requires a small 3 inch hole in a wall to get the tubing from the outdoors and into the house.
Attic hvac systems save space.
This pan needs to be at least 1 1 2 deep.
So why put an hvac system up in the attic at all.
Sure if you can find enough space and afford the large cost to have someone poorly carve up the inside of your house to get the proper sized ductwork through the house.
The only thing connecting the two components are a small set of tubing.
Regardless of the air handler type you choose a separate compressor unit is installed outside to power the indoor unit.
A drain pan with a separate drain a separate drain pan can sit underneath the unit and this drain pan needs to have its own separate drain line.
Install a zoning system.
With separate central air conditioning units for each floor of your home you can maintain a comfortable temperature for each defined space.
Good luck getting better cooling in the upstairs in an old home using a basement hvac system than one in an attic.
Quit writing papers and go try a seat of your pants experiment.
Attic fans that exhaust heat and upgraded insulation in the attic floor can reduce attic heat accumulation and keep upstairs rooms cooler without lowering the thermostat.
This not only improves comfort but can also enable you to save money on utility bills.