Our old 3T unit from 1977 is kaput. Its gas heat/electric cool. We live in a hot inland valley in CA - cooling is most important. The old unit was ineffective against the 105 degree days we had so often last summer.

Have had a few dealer/contractors though and have gotten

1) 4T Rheem unit rooftop installed $6500 (guy offered few details but he is known/rec by a friend electrician who used him for his house.)

2) Carrier Infinity 13 with Puron Refrigerant rooftop installed $5500

3) Off label 4T unit with SEER 13 also (Goodman?) offered at $4800 installed

Still waiting on the Trane guy to show up.

I have no idea what I'm doing and what questions I should be asking. Are the big brands worth the added cost? Any recs on which is best for a 1700sqft home (thinking of addition)? Thanks.