The model number of the Goodman furnace is GMSS961005CNAA. Looks like it is 96% efficient. The existing A/C is Carrier, I believe model number 38TM048300, but I can't find that in the AHRI database.

The cash settlement is a good idea. I'll investigate that option. The good thing is that the unit is still working (for now) so we have a little time to figure out what we want to do.

Here is the link to the Goodman warranty.

Unfortunately it only applies to the original owner. Ask the seller if he registered the furnace. If he did not, then go to the Goodman web site and register yourself as the owner. Registration gives you the 10 year warranty period. If you don't have the paper work you be able to get the serial number from the furnace.

This is a basic high efficiency furnace. I think you should buy the matching Goodman AC condenser and coil. Do periodic maintenance and you should get 10+ years out it.

Nothing wrong with Goodman equipment. Get the Goodman AC condenser of your choice (13-16 SEER) and matching coil. As long as its installed correctly, it'll last as long as any other brand and should be good for at least 10 years.

above post very optimistic about the Goodman components...not a brand I like or would purchase....but based on circumstances, I would add a Goodman condenser with matching evap coil...plus hold my nose!...

IMO

I've had a couple (I think reputable) HVAC contractors out to quote the replacement. So far, none of them have measured any rooms or windows, asked about or verified existing insulation, or counted registers. They did look at the overall size of the house and percentage of basement vs. crawl space. With the most recent one, I specifically mentioned that one room is particularly warm (we have only been in the house during cooling season, so I'm not sure how it performs in heating season). He suggested insulating the ducts (they are currently un-insulated through a crawl space) but did not suggest verifying CFM to that room.

Surprise, surprise, the quotes have been coming back the same size as the existing unit (4 ton) or 1/2 ton smaller. Should I be expecting a more thorough analysis before receiving a recommendation and quote? I asked the last guy about this and he said they "guaranteed" the correct size. If we needed bigger or smaller after install they would change it out at no charge. I'd rather know it was sized correctly and just install the correct thing the first time. Any advice would be appreciated. Thanks in advance!

A good contractor will do a load calculation. Many will either replace with the same size or use of rule of thumb of 600 sq. feet per ton. Trying to get a contractor to swap incorrectly sized equipment is usually a tough fight. They will work very hard to convince you it is the right size.

If the current AC is working and it is running in short cycles then it is too big. The new one will also do this.

I would replace the A coil, and the capacitor on the condenser. Hard start kits are only $20.