In Atlanta / one-story / 1,800 sq ft / furnace in attic / easy installation / both quotes from reputable contractors / Quotes nearly identical without upgrades, and at top of my budget (taking rebates/tax credits into account) but can finance if some upgrades worth it.

CARRIER - 4 ton Comfort 16 Two Stage, non-variable furnace, under 75 db

VERSES SIMILAR $ QUOTE FOR...

TRANE XR13, R410a, 4 ton, as low as 75db
with 5 ton furnace XV80 (told the 4 ton is the same price, so 5 ton included "for free")

My concerns
*Is there a significant difference between Trane and Carrier parts/engineering?
*Is a variable speed worth a $1000 difference?
* Is a 5 ton furnace with a 4 ton compressor problematic?
*Which is quieter? Is there a way to test my current system's db, which I know is too loud?
*Is there another suggested brand within range of these systems?
*Who are you guys answering these questions? :)

Thank you!
Ashley

How do you heat? I"m assuming since your in atlanta you are familiar with heatpumps. You want one if you don't have one (for atlest the mild heating days).

Which Carrier furnace mdl? Generally you can not pair a two stg condenser without a var speed furnace.

What size/efficiency furnace are you replacing? What size AC are you replacing?

I certainly would not recommend the larger XV80 furnace. It will only cost you more to operate. Shame on that dealer.

I do recommend a two stg furnace with var speed blower.

Dealers are quoting new line sets? What about whole house filter cabinets? What mdl thermostats? What mdl evap coils. These are not insignificant details.

IMO

2 Quotes, both @$6,000 (another Carrier quote of $9-11,000 was so out of budget)

Thank you for your insights. See new details/answers below.
"What mdl. thermostats? What mdl. evap coils? These are not insignificant details."
"Generally you can not pair a two stg. condenser w/out a var. speed furnace"

CARRIER
4.0 Ton, 16 Comfort Series Gas Furnace 16 SEER Rating
Comfort Series 16 A/C (24ACC648A003)
Coil (CNPV 4821)
80% Performance Boost Furnace (58PH0110-16)
Carrier Thermostat Edge

VERSES

TRANE
XV80% afue 100,000 BTU Variable Speed 2 stage gas
furnace Model# TUD2C100A9V5VA and the Trane 4 ton XR13 SEER high efficiency
R410a Puron air conditioner Model# 4TTR3048D1000A and Trane 4 ton all aluminum
cooling coil Model# 4TXCC049BC. Trane Touchscreen Super Dehumidification
Thermostat Model# XL803

"considering the carrier is a 2 stage comfort series and costs $1,000 less, go with it..."
It is $1,000 more (not less). Is the long-term savings of variable speed worth the upfront upgrade cost?

"certainly would not recommend the larger XV80 furnace. It will only cost you more to operate..."
Thank you, we were questioning this

"are you familiar with heat pumps. You want one if you don't have one�"
That would be a $600 upgrade. Is this worthwhile?

"Dealers are quoting new line sets?..."
I don't know what this means?

Still wondering
*Is there a significant difference between Trane and Carrier parts/engineering?
*Is there another suggested brand within range of these systems?
*Who are you guys answering these questions? 

When going from the older R22 refrigerant to the new R410, the pipe sizes are usually different.

For a $600 upgrade for a HP, it would depend on your current electrical and gas rates and how long you are going to stay in the house.

The 2-stage heatpump-A/C running most of the time in the low-stage during cooling to dehumify better will provide better comfort.

I don't think the carrier heatpump offers demand defrost which is a downside to it. Trane models do. I would still go with the carrier model since its higher efficient on the A/C and you will be running this alot.

I would run the heatpump when above 35 degree's and use the gas furnace at anything below. The heatpump will provide a evenly heated rooms in this temperature range do to the longer run cycle's of warm air.

Ask tiger for your Energy calculator to compare the cost of heat from the different methods of energy. Keep in mind the COP of heatpump heat is 3.5 or more at 40 degrees and above with a modern high-efficiency heat pump.

I would recommend a load calculation for correct sizing both heating and cooling.

I know the Hotlanta climate very well-hot summers, relatively moderate winters.

I have always thought the sweet spot for Atlanta HVAC is two stg 80% eff var speed furnace paired with high eff heat pump. If you provide your electric and nat gas rates including all applicable and recurring mthly fees, I will be glad to run a comparison of the rates to see if HP can be justified.

Just to be clear what size is your existing AC and what size and efficiency is your existing furnace?

Post back.

IMO