chambery

if you really want an answer approaching an informed opinion, you will post the mdl numbers of the furnace, evap coil, and condensor for each system.

I will say this. you want a furnace that has a var speed blower. and you do not want to leave the fed govt tax credit lying on the table.

IMO

If you ask me, I like the Carrier/Bryant systems. I like the Thermostat controls better. From Carrier/Bryant you can also choose a hybrid heat system which I recommend you at least look into.
There should be fall rebates starting soon on certain systems so you can save a little more with that. An Authorized Dealer should be able to give you an instant manufacture rebate.

Next a load calculation is a preferred method of sizing an air conditioning system. It is mandatory in new construction. If your house is older than 20yrs then it may be good to have a load calc done. However it is Not the Answer to everything. It is only as good as the inputs and It is more used as a sales tool in my opinion.
I've been doing load calcs since 1989 and some estimates I will use it if it is requested but for the most I don't do a load calc. I rely more on looking at installation, customer input and duct. If the customer wants the absolute facts on there home then we can do an blower door and duct blaster test on the home then do a Load Calc. But time is money and these things really can't be properly done for free.

If you like a contractor over another contractor and his price is higher you can ask him if he will reduce his price to meet or get closer to the other contractors price, this is normal.
Keep in mind you can't compare an Authorized Dealer with some jackleg's price. The customer service and reliability of the company is a major factor to consider.

Good information and advice, thanks.

I do plan on a variable speed blower. Load calcs were performed and one of the contractors did as you said ClassicDave, he asked alot of questions about my existing system's performance and what I like or disliked about it.

The model numbers I have so far are on the carrier system

24ABB449 4 ton A/C
CSPH6012 5 ton E Coil
58CVA090-16 90,000 BTU 2 stage variable speed blower

This system is rated at 45,500 BTU cooling capacity, 16 SEER and 13 EER.

Checking the AHRI website for Carrier systems, the only 4 ton E Coil that qualifies for the tax credit had to be mated to a 155,000 BTU furnace.

I am supposed to get formal quotes with model numbers from the Trane / Lennox dealer this coming week.

Here is a link that might be useful: http://ths.gardenweb.com/forums/load/hvac/msg082325342972.html?2

chambery

the condenser quoted is Carrier's bottom end base mdl.

with today's expensive fuel rates, an 80% eff furnace is a mistake unless paired with a matching high eff heat pump.

IMO

There are no Comfort series with a Carrier E Coil that qualify for the energy credit. The Comfort series is estimated to save $23 per year over the Base model, a payback of 65 years ($1,500/$23). And the higher price of the Comfort series is not factored into that payback period. The Carrier dealer is offering 10 year all parts warranty as part of the price. So no difference there. Located is a brick corner at the remotest corner of the house, sound is not an issue and at only 4 dB greater sound rating, I would rather enjoy the dollars saved. I'll have a variable speed fan and Thermidistat to achieve proper humidity control.

I have made a note to ask the contractors about the HP option again. We briefly discussed it earlier and the initial cost was high enough that I calculated a payback that was not justified. Given my opinion, FWIW, that electric rates will rise much faster than nat gas rates over the next 10 to 20 years due to the current and expected continued glut of nat gas supply on the market and in the ground combined with the likelihood that this cap and trade energy legislation will pass causing all electric generating companies costs and our bills to rise dramatically, I expect significant savings by using gas relative to electricity, Again, just my opinion, but also my dollars. I hope it doesn't actually happen.

But I will explore the HP option again.

Thanks for your suggestions.

Here is a link that might be useful: http://ths.gardenweb.com/forums/load/hvac/msg082325342972.html?4

You are correct there is no carrier comfort 4 ton a/c system that meets the 16SEER 13EER as the 24ABB449
Personally I'm not a fan of the Carrier Base models but it just blows my mind how Carrier/Bryant only makes a 49 and a 61 in the Base model and not in the comfort.
It's the way to go but see if they will throw in a sound blanket for the compressor.

That and a thermostat is what I had in mind, and a reduced price on a 10 year labor warranty from the contractor. Can't hurt to ask.

Thanks ClassicDave

Here is a link that might be useful: http://ths.gardenweb.com/forums/load/hvac/msg082325342972.html?10126