Hi there, here are some of my thoughts, hope it helps...

1) yes they are pretty base level but one's giving you 13 seer and the other is giving you 14 seer which is higher efficient.
2) well, that really depends on your budget, if you don't mind spending a little more then that's fine.
3) york, trane and carrier all made good products so you can't go wrong with any of them but york do has the smallest size condenser of the three.

Please email me if you need more info admin@gsistore.com

I'd recommend a variable-speed furnace for more comfort and efficiency. Make sure you have sufficient return air ductwork. Carrier's ABA is the builder model; the ACA is better (Comfort series). Carrier, Trane and York all make good equipment. Ask for the specific Carrier coil model #. The ACA coils have been prone to leaking, but the ATA coils are better (these three letters are at the end of the model #). I personally prefer Trane over Carrier. Sizing is the more important issue here. Did you share sizing information among contractors, or did they all come up with 3.5 tons? A Manual J is absolutely necessary for a home that had no A/C beforehand. Companies are proposing different size furnaces when all that is needed is a Manual J to tell you what is really needed. That doesn't help the comparison, does it?

Those sizes are amazing! No insulation? All windows? Around here, we get below zero in the winter and 95 and high humidity in the summer. That house would be 2 or 2.5 ton cooling and 60-70,000 BTU heating or less if newer. Seems like they are putting some huge equipment in a small home. I wonder if the ducts there could handle any where near 3.5 tons of airflow (1400 CFM).

1500/500 = 3 tons + 1/2 ton just to be sure = 3.5 tons. Perfect! :D

Thanks to everyone for your replies and advice!

ryanhughes -- No, I did not share sizing info among contractors; they all came to 3.5 tons on their own. I did, however, mention to Company 3 that I already had an estimate for a 90K BTU furnace, so Company 3 guy said, "well, I was going to suggest 80K, but in that case, let's go with 100K." Also, I did let all estimators know that I'm planning to add on 150-200 sf in the next year or two, so they should take that into consideration.

baldloonie -- Nope, not much insulation. some was blown into the attic floor in the 70's, so it's (somewhat) compacted now. Otherwise, nothing at the roof, in the crawlspace orin the walls. And yes, lots of windows -- at least those have been upgraded to double-pane. It's been stinkin' hot this year with several weeks of 90+ temps so far... and we're probably in for a few more (it's a dry heat, though ;-)). Winter nights can get into the 30's during cold years.

A few more questions...
1. Company 3 also sells York, and I'm looking into the LX series A/C for space reasons (smaller footprint). In terms of sound levels (dB's) nd reliability, what's your take on Carrier Comfort/Performance vs. Trane XR13/XL14i vs. York LX series?

2. Would I be better off with a completely matched system (e.g., Trane furnace/Trane A/C), or can I mix and match furnace and A/C (e.g., Trane furnace, York A/C)?

3. A couple of the estimates I received included the option to add on a higher-end air filter -- Carrier Infinity (Company 1) or AprilAire 2400 (Company 3). Is it worthwhile to do this?

4. I have allergies and pets. Is there a noticeable difference in adding an air cleaning system? I guess the real question here is "are they worth the money?"

5. Company 3's estimate is about $2K higher than the other two. I assume this is due to the higher price of Trane components, the additional fabrication for the sound-attentuation work, and their fabrication of an "accessible" filter box. Thoughts?

First and most important Does your current return reside near the floor? Is there only 1 or 2? You see the point Im getting at is that cold air falls, if all your registers are in or near the floor then you will need a return located high up to pull out the hot air and draw up the cool air. In my parents house I replaced there furnace as well as added A/C and since there return was on the wall but low to the floor I installed a second high up. In the summer I have them close or block off the lower return (by covering there filter with plastic or cardboard then reverse this in the winter covering the high return. This is more important than you might think more important Than SEER ratings. If highly efficient equipment runs constantly because the T-Stat never satisfies then it is no longer efficient. As far as York dont go with it. The four I only consider are Trane Carrier Rheem and Lennox.

learningtoo -- thanks for the reply. The return is located in the ceiling, away from registers. Thermostat is located at the opposite end of the hallway from the return. Can you say more about why you don't like York?

"As far as York dont go with it. The four I only consider are Trane Carrier Rheem and Lennox."

Care to share an explanation as to why? York's Affinity line of equipment is some of the best equipment on the market--quiet, too. I agree with your other choices, but why you left out York is what I'm wondering.

Note I say "some of the best." There are many good brands of equipment out there to choose from. York is just one of them. What I mean is York's Affinity line is their upper line of equipment that can compare to the higher-end equipment of other brands.

Dear alg_ca: Just read your posting after a Google search on furnaces. I'm in the SF Bay Area too, El Cerrito/Richmond hills and have been reading and posting on GardenWeb for a couple of weeks in an effort to get some good advice. I'd been quoted on American Standard, Rheem and a Ruud/York combo. I like the idea of the Ruud/York combo as it's very quiet but have been amazed at how quiet some of the Bryant and Carrier units are. I found a couple of sites that have recodings of the start up and running noise levels. Is your new unit quiet? Well, what did you eventually decide and which quote did you go with? Care sharing the dealers you had come over? Are you happy with the product you finally installed and the work the company did?

Almac, I'm not sure if these forums let you know about new posts; I know I get no notifications. This is from July, so I wouldn't count on the OP returning.

I can give you general advice:
- As far as outdoor units, most products on the market above builder's grade are quiet to the average person. Inside, I'm not sure with furnaces since I don't have one, but I'd say if you're going with one of the upper-end furnaces, especially multi-stage furnaces, you're likely safe. Hopefully others here can share experience with their furnaces. Rheem supposedly has a very quiet furnace which they label the "Super Quiet." And I would stick to the same brand inside and outside to get the proper AHRI match for the certificate (needed for tax credit), but you can mismatch provided the indoor A/C coil and outdoor unit match.

have then check static pressure in the system... it tells alot about alot