Did the current 4 ton system keep the house cool on the hottest days? If the answer is yes, then 4 tons is the correct size.

Why do the five contractors want to increase the condenser to 5 tons? Did you indicate any cooling issues?

Did the contractor who did the Manual J calculation review it with you? Do you know the what the cooling load and the indoor and outdoor design temperatures?

It is good to see the contractors are recommending changes to the duct work in order to handle the 5 ton system. Most houses don't have the duct work to support the air flow (2000 CFM) for a 5 ton system.

If you are paying for a 10 year labor warranty, then I would want it from Trane and not the contractor.

-On the hottest days the old A/c unit struggled to keep the house cool at the desired setting.

-Yes, I indicated that the whole right side of the house was hotter than the left side, but probably bc of the poor duct layout that is being corrected.

-Here are some of the #'s off the Manual J, I don't really know which #'s you need... this document is like 6 pages long...
-Building Loss 52,075 Btuh
-Building Gain 41,587 Btuh

Building Loads
-Total Heating Required Including Ventilation Air: 52,075 Btuh 52.075 MBH
-Total Sensible Gain: 35,827 Btuh 86%
-Total Latent Gain: 5,761 Btuh 14%
-Total Cooling Required Including Ventilation Air: 41,587 Btuh 3.47 Tons (Based on Sensible + Latent)
4.15 Tons(Based on 72% Sensible Capacity)

Whats the benefit in labor warranty from Trane or the dealer? Trane labor warranty just makes it universal for any dealer to do the work?

With the figures provided will a 5 ton system be overkill and cause the system to run and shut down too quickly thus causing efficiency issues/ future mechanical problems/ not properly cooling the home? Thanks again

The Trane labor warranty allows any Trane authorized dealer to do the warranty work. This protects you in case the original contractor goes out of business. Also the costs for the labor are covered by Trane and the not the contractor. This is nice to have in case you have several expensive repairs during the warranty period.

Since the Trane XL20i is a 2-stage condenser, a 5-ton unit with your cooling load will likely run in the low stage most of the time. I don't know the split on the stages, but it is likely to be in the 3.0 - 3.5 ton range. It would likely still do a good job with humidity control and not short cycle, but it still would be a concern for me. I would also be concerned about having adequate duct work to handle the 5 ton unit.

You stated contractors are offering the 5-ton unit for much less than the contractor who did the Manual-J calculation and recommends the 4-ton unit. Are you sure you are doing an apples to apples comparison of equipment and installation?

Aapkook

Three concerns.

1. Correct sizing 4 ton or 5 ton
2. Ductwork sized correctly for new system including adequate return
3. A 5 KW heat strip is undersized to handle defrost calls to temper air; and yes defrost calls would be rare, still. And also a 5 KW would do you little good if you had to go to emergency heat due to condenser breakdown. Yes I know this would be rare, still.

IMO

All technical matters aside what do you think of the quote @ $10,900? Thanks for all the great tips I really appreciate the help.

aapkook

You should insist on new refrigerant lineset regardless which size you select.

Ductwork should have a thorough inspection-size both trunk lines, supply runs, returns, leak test, insulation quality.

As fas as pricing it seems to be typical Trane pricing-I've seen both worse and better.

IMO

Mike, to answer your previous ? The installer with the highest quote was trying to sell a 4 ton unit by Trane
-Model 4TWZ0048A1000
-Model TAM7A0C48H41
-Model TCONTT803
-Less Ductwork modifications
$12,691

And with the other contractor I am getting higher end units, 5 tons, and more duct work for $10,900... However I did feel like the 4ton guy was an excellent technician very smart, but way over priced. But I feel like the $10.9k contractor is more than capable of doing a great job... I just hope I can save some money on my power bills! I was paying $330 a month, but we do have a pool. But my old unit was a POS...

Tiger,
They are installing an all new refrigerant line-set. I went ahead and made the appt and accepted their offer... They threw in the 10yr labor warranty at no additional cost. I'm not really worried about them going out of business they have been around since 1969 and are one of the largest residential HVAC contractors in Orlando. I hope all goes well! Thanks for all the help Tiger and Mike