I would really appreciate any help with my new AC system.

I live in Dallas, Texas in a 1,900 square foot home. We usually keep the temperature at 74 degrees in the summer and 76 degrees in the winter. Our main priorities for new system are reliability and cost savings.

We will be replacing the entire system - new duct work in attic (previously in crawl space), move system to attic with new copper line from outside unit.

First, the quotes we have received for the duct work were 3,200, $4,000, and $4,900. My concern here is the wide discrepancy is price. They all seem to quote similar materials so not sure why the price is so different. Do these prices seem reasonable?

Now to the units...they have all indicated I need a 4 ton.

Contractor 1 - Duct work $4,000
Option 1
Trane XR17 Condenser - 4TTR7048A1000A
Trane XV80 - TUD2C080B9V4V4
Trane R-410 Cased Coil - 4TXFH054CC3HHA
Trane High Definition Thermostat - TCONT824AS52DA
Cost - $10,500

Option 2
Trane XB16 Condenser - 4TTB6049A1000A
Trane XT80 - TUD1C080A9H41B
Trane R-410 Cased Coil - 4TXFH054CC3HHA
Trane High Definition Thermostat - TCONT824AS52DA
Cost $9,200

Contractor 2 - Duct work - $3,200

Option 1
XC16-048 Lennox Elite 16 seer two stage
SL208DF090V60C Lennox variable speed/ two stage heat gas furnace
CX34-48C Lennox High efficiency coil
iComfort touch-control thermostat
Cost - $8,700

Option 2
24ANB748 Carrier Infinity 4 Ton 17 SEER two stage capacity
58CVA090-1-16 Carrier infinity variable speed/ two stage heat gas furnace
CNPHP4821ALA Carrier High efficiency coil with safety float switch
SYSTXCCITW01 Carrier infinity touch-control thermostat
Cost - $9,800

Option 3
Carrier Comfort Series Air Conditioner (24ABC6)
Carrier Performance Boost 80 Gas Heat Furnace (58PHA)
Performance N Coil�Horizontal (CNPHP)
XC14-047 Lennox Elite 4 Ton 16 SEER Single stage capacity
EL180UH090E60C Lennox Elite high performance gas furnace
CX34-62C Lennox High efficiency coil
Honeywell Lyrics thermostat
Cost - $7,810

Contractor 3 - Duct Work $4,900

Option 1

Comfort Series Air Conditioner (24ABC6)
Energy Efficient
Performance Boost 80 Gas Heat Furnace (58PHA)
Performance N Coil�Horizontal (CNPHP)
Nest Thermostat
Cost $10,300

Option 2
XR16 Air Conditioner (4TTR5)
XV80 Gas Heating Furnace
Trane Comfort� Coils
Nest Thermostat
Cost - $10,400

Also, I have another contractor coming tomorrow that will give me a quote for a Daikin but I am not as familiar with this brand. Anybody know anything about this brand and is it worth considering?