Why do you use the air conditioner only one month out of the year? Are you summers very mild?

If you don't have hot summers, then I question why you need a 5 ton AC condenser for a 2300 sq. ft. house. It seems very over sized. Why are you replacing a 10 year old condenser? What is wrong with it?

A couple of things.

I would like to see the details on the Trane quote.

Not a fan of Lennox, just so you know.

The ACX condenser models are low end and if not mistaken made South of the Border. May not make a difference to you.

The dealer on quote #2 is grossly overcharging. Throw him and the quote overboard.

If intent on the Lennox brand, then go with XC13 AC condenser. Worth the price difference which should not be more than several hundred dollars. You would want the 90 K BTU ML180E model furnace with 5 ton rated blower. That's if you really need a 5 ton condenser. Like Mike questioned above, not sure that a 4 ton would not do the job. Keep in mind you size to the average not the rare extremes.

IMO

Good to see tigerdunes posts again.

He needs to tell us where he lives; a 5-Ton is nearly always way too big for the duct system & Return air filter sizing.

Here is a free Whole House load-calc at anyone can learn how to use:

Here is a link that might be useful: Whole House load-calc

OP lives Southwest Ca....

I would think that a new system would be more efficient and therefore you should be looking at the slightly smaller 4 ton units. Replacing an old inefficient 5 ton with a new higher efficiency 5 ton would grossly oversize your system. I would only buy a unit using 410A refrigerant. The low road is to continue to try to make your old R22 system work, but the R22 is brutally expensive today, not as environmentally friendly and will only escalate in cost.

My question for you is, what do you mean the "ductwork is good?" How do you know that? Have you had a third party do the duct test? What rate of leakage is there?

Thank you for all of the input. A third party did clean our ductwork not long ago, and told us it was in great shape. A HERS (Whole House Home Energy Rating), duct leakage testing is mandatory in CA when installing or replacing HVAC system. It was included in both bids, $250.00.

Part of the bids were to do resealing and add insulation.

As to the 5 ton versus 4 ton, I gave you the wrong sq. ft., it is a little over 2,500 sq. ft. Both contractors recommend the 5 ton. When I questioned again after reading your responses, the first bidder again recommended we stay with a 5 ton.

Trane: Contractor said our space was to small for the coil? on the Trane. If he went that way, would need to use an after-market part to make it work, and didn't want to do that...

Mike, we do get hot weather: few weeks of 90's but can get up to 110 infrequently in the summer. 60's day but down to the 40's night, occasionally 30's, winter, but try not to overuse our units. Keep it in the mid to high 80's summer, high 60's winter. Turn off at night. Try to do our bit for energy conservation.

Bid on XC13 AC condenser, $200.00 more on first bid. 90 K BTU ML180E model furnace with 5 ton rated blower,
$600.00 additional. Total $6,549.00

I hope I answered all the questions. Thanks again.

With a 5-Ton system there is rarely a large enough Return Air Filter area(s); normally needs two extra large filter areas.

Duct system is usually not large enough or have enough supply runs for 5-Ton of airflow

They should do a proper ESP static pressure test to find out if it's too high foe 1750-CFM the lowest 5-Ton airflow.

Here is a link that might be useful: ESP Duct static pressure TEST