Interested matchup in the second quote with the 80k/4ton furnace mated with the 5ton outdoor unit -- but it is a rated and approved match according to AHRI and Trane. Important in that case that they set the blower to the highest speed option.

Quote #2 doesn't appear to use the communicating XC80 and communicating XL900 thermostat. If you go with this option, I'd try to get them to substitute the models, since if the outdoor unit can be communicating, it would be a good move to take advantage of the ComfortLink II system.

Thanks - I'll ask about this.

Any comment or advice about the different load calculations?

A load calc shouldn't take 6 hours.

Obviously some are right on the sizing, and some are wrong. So essentially we're looking at a 4 ton or a 5 ton unit. If 4 tons is the size required, then it would be less efficient to use another 5 ton. It is said that today's units don't dehumidify quite as well as older units - another reason to get the sizing right. I'd ask to see the calculated heat gain/loss figures from each company. Really can't say much more without evaluating the home and doing a Manual J. You mention the 5 ton kept the home comfortable but ran short cycles. The good part about the 20i, however, is it has roughly a 50% capacity drop in low stage, so low is around 2.5-2.75 tons.

Thanks. I'm new to all this. I was reacting to some of the posts on this forum from people stating the load calculation took 6 hours, and some people were charged for it. It made me wonder if the 2 dealers who did it in a few minutes were just guessing.
It's already 96 degrees here in Phoenix and right now my A/C is in cycles about 10 minutes on and 20 to 30 minutes off. Maybe that's normal.
I do appreciate the feedback you've given.

96 degrees is hot to have it cycling with 10 minute run times, even though I know it can get warmer there. You may want to call another reputable, reliable company or two, and express your concern with proper sizing with them on the phone. That way, they don't waste your time and vice versa.

What unit/ton did you end up with John? Also would you mind telling me who your installer was and are you happy with the job they did?

TIA

We now plan to go with 4 ton XL20i. Haven't done the install yet, we've been delayed a bit but should get the work going soon.
The contractor has paired this XL20i with XV80 furnace, I'm not sure I understand the difference between this and the XC80 even after reading the info on the Trane website. There's probably still time to change this if I need to go with XC80.
Any advice?

No, sorry. I'm just in the starting stages and was really interested in a GREAT installer. We have no friends/experience with this. Thanks for the reply.

I highly advise you get it changed to the XC80 before it goes in. Without it, you cannot use the communicating features of the system nor the TCONT900 control, which would be unfortunate for that kind of money.

Thanks, I will talk to the installer in the morning.