What size living area?

By moving up in size from a 2 ton condenser to a 3 ton, that is an increase of 50%. Has any dealer bothered to check your ductwork system to see if it is sized properly for additional CFMs?

Linesets must be sized correctly. It is highly unlikely that existing lineset would be correct size for larger AC condenser?

Do you currently have adequate return (s)?

I prefer the HW VP IAQ stat that is a true two stage thermostat plus has dehumidify on demand feature.

I want a system that qualifies for Fed Tax Credit.

I want a 4-5 " pleated filter media cabinet.

IMO

I've posted a couple more comments to your original thread. The prime concern right now, as TD mentioned above, is ductwork sizing with most dealers wanting to move up to 3 tons for an 1100 sqft upstairs. Have you seen the actual load calculation results? Sometimes dealers will not reveal their results until you sign a contract, but knowing your actual calculated heat gain (both latent and sensible btu's) aids in system selection. If falling between 2 and 3 tons, with 2-stage systems only coming in full ton sizes, most do tend to upsize. Hence the need to ensure ductwork (both return and supply) is adequate to support the airflow.

This post was edited by ryanhughes on Sun, Jul 14, 13 at 18:49

Tigerdunes and Ryan,
The living space is 1120 sqft, but the cooling area is abt 1350-1450 sqft according to calculations done by contractors.

Most of the contractors have just told me I have enough ducts for 4 ton system. I will be talking to one contractor who did load calculations to find out the real numbers. I have one return in the hallway and they all told me it is good for a 4 ton system.
Is a Rex rack a good product? Is it a perfect fit with the Trane furnace? I figured out that the furnace listed is oversized so as to meet the Tax credit EER value and SEER. I really do not know if it makes sense to go with a 2 step condenser and 2 stage oversized furnace just to get $300 tax credit. I am thinking of going XR15 with 2 stage 60000 BTU furnace or XR15 with XT80 furnace . If the actual tonnage per load calculation says 3 tons, I may still want to go with 2.5 tons.

I am also getting quotes for American Std, hoping they will be cheaper than Trane. What is the american std version of XR15? Is it Gold XI or Gold SI?

At

Ok. I did talk to one of the contractors and she said the Return will be increased for the increased CFMs.
What is the purpose of dampers? What benefit do they bring?

Thanks