Carrier thermostat - performance edge on infinity furnace?

[atlanta-bungalo]

Questions:
- Can i use a performance edge thermostat with an infinity furnace? Or is that lame?
- Do I need a dehumidifier to deal with atlanta humidity, or will this setup work?

I have an 1840 sq ft single-floor house built in the 1930's with original windows and limited insulation, in midtown Atlanta. Replacing a 3.5 ton AC unit (GE from the late 1970's, we think) and a comparably old furnace (contractors guess the furnace is about 50% efficient...) which worked ok but loud and humid inside on humid nights in the 70s outside.
The chimney appears to be inadequately lined so contractors are recommending a 90%+ furnace to use PVC exhaust out the side of the house.
My main goal is to deal with the humidity here, without going crazy on cost.
The recommendation is consolidating around this kind of setup:

Carrier Infinity furnace 59TN6A080V17-14 (to get real variable speed and humidity control)
Carrier performance EDGE thermostat TP-PRH01
3.5 ton ~13 SEER AC compressor unit 24ACB342A003
Matching evaporator coil
Honeywell F100 media air cleaner.

What do you think?

Thanks!

[atlanta-bungalo]

Incidentally two contractors came up with 3.5 ton recommendations, one claims a full load calc behind that. Another recommended 3 ton. All said the old, leaky house requires more AC than new houses.

[comfortdoc]

Money spent on building envelope improvements would go a long way toward reducing the system size and energy costs. If humidity control is important, step up to the Infinity control.

[lkapigian]

X2 on comfortdocs reply