2 carrier options- 2 stage 4 ton 17 seer or 3.5 16 seer

[zhackwyatt]

Hello all,
I own a 2700 sq. ft home in Phoenix, AZ with vaulted ceilings.

I have two options in front of me and I am not sure which is better:
Option 1:
Both performance series, single stage, boost furnances
Upstairs: 2.5 ton 16 seer
24apa530a003, 58pha090116, cnpvp4821ata
Downstairs: 3.5 ton 16 seer
24apa542a003, 58pha090116, cnpvp6024ata

Option 2:
Both performance series
Upstairs: 3 ton 17 seer
2 stage condensor to variable speed furnance
24apa736a003, 58cva090116, cnpvp4821ata
Downstairs: 4 ton 17.5 seer
2 stage condensor to boost furnance
24apa748a003, 58pha090116, cnpvp6124ata

Any recommendations?

It is my understanding that the Boost is cheaper than the Variable speed and more efficient.

The thermostat is the Edge Programmable.

I'm looking for the option that will save me the most money over the long term. I wasn't sure if the 17 seer was that, since it was a higher tonnage as well.

Thanks

[beenthere]

Helps if you post your location. So people know your weather/climate.

[zhackwyatt]

I did, I said Phoenix, AZ.

I'll update my location in my profile though too.

[beenthere]

Guess I should have had my glasses on. LOL

[udarrell]

Upstairs: 2.5 ton 16 seer
Downstairs: 3.5 ton 16 seer

What is the sf area upstairs & downstairs floors?

If they are equal, there is usually a heavier heatload on the top floor rooms.

Does the 2.5-Ton unit handle the top floor heatload?

Was a manual J load calc performed on each room, on each floor?
Was a manual D performed on the duct system & air handler?

Well, 2.5 plus 3.5 is 6-Tons for a total of 2700-sf.
Maybe you could do some things to reduce the 6-Tons?

I know, it gets hot in Phoenix, AZ, - however... - Darrell

[zhackwyatt]

Upstairs accounts for roughly a third of the space. I don't have the exact numbers with me.

The 6 tons are what the builder installed on the home.

No the load calcs were not done. I am getting the ducts sealed by another company. The home has not been modified since it was built. I'm happy w/ the performance of the existing system, other than the fact they are 14 years old and 10 seer.

[udarrell]

Upstairs accounts for roughly a third of the space. I don't have the exact numbers with me.

The 6 tons are what the builder installed on the home.

No the load calcs were not done. I am getting the ducts sealed by another company. The home has not been modified since it was built. I'm happy w/ the performance of the existing system, other than the fact they are 14 years old and 10 seer.

If the existing systems are costing you too much, they may never have been operating at peak efficiency, very few are.

I'd have the airflow CFM & duct systems checked for optimal performance.

With the same heatload conditions, the 10-SEER units use a larger capacity compressor which operates at a lower suction pressure & evaporator coil temperature.

If sized right to the heat-gain load, 10-seer units do a good job cooling.

You may have more run-time with higher SEER equipment. Let us know how much you save, the payback period, & how well you like the new systems.

The quality of the install & total setup are the main factors affecting new equipment performance!

High SEER units do work better in dry climates. - Darrell

[zhackwyatt]

I'm still not sure which of the 2 options is a better choice for me.

Any opinions?