A lot of installers do not understand how to set these systems up. The IAQ can dehumidify by slowing the blower on a variable speed air handler equipped with a connection for that purpose. The IAQ's EM must be wired to the AH correctly for this to happen. The IAQ must also be programmed correctly, and the AH may also have to be set up correctly (don't know about a Trane). And here is the big one, it only work when the system is in the air conditioning mode and is actually actively cooling. To dehumidify while heating, you would need a dedicated dehumidifier. The IAQ will also control that, if it is set up and wired properly. The dehumidify by slowing the blower bit works by shifting the system's latent/sensible cooling characteristics. In the dehumidify mode, it biases it toward latent at some expense to the sensible. If you don't understand the terms latent and sensible as used in the HVAC industry, you will probably need to do some reading up on the subject to make sense of this post.

-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 answer to your HD question- Yes, no or maybe. All kidding aside, your local Trane dealers enter into contract with HD to provide their services under the HD umbrella. Yes, HD gets a cut, something like 25-30%, depending on market, however, the contract services to HD are less since, HD is providing the leads, sales and many times the financing. So you see, HD can be competitive however if you choose to solicit their services, it is always good to compare with other brands and/or dealers to find a reputable company that you feel will give you the best install, service and fair price.

You're right, remove the "B" from the model#. That's a basic Trane XR13 a/c. Should run like a champ. Great price. Depending on how often you run the system, a 10 year parts and labor warranty should be considered. Labor is typically 1 year, parts 5 to 10 years for the mfrs warranty. Good luck.