The XL15i is Trane's highest efficiency single stage system and a very nice unit overall. In your case, for a new build, your primary focuses should be proper equipment/ductwork sizing and a quality installation. A properly designed system with good ductwork will help ensure year-round comfort. A 2-stage, variable speed system is an upgrade. The 2-stage system will provide better comfort throughout the home with longer runtimes (hence the need for a properly sized system, single or 2-stage) and therefore more dehumidification. I recommend a variable speed indoor air handler regardless of whether you choose the XL15i, XL16i or XL20i heat pumps (or other). While their summer dehumidification benefits may not be as important to you, one of the main advantages is the blower's ability to maintain a constant cfm (airflow) across varying duct conditions. This means that if the ductwork is less than adequately designed, or if your filter gets dirty and total system pressure drop increases, your airflow won't decrease and the motor will work harder (increase rpm) to meet the required airflow (up to a point, typically 1" external static pressure). This protects the equipment and maximizes performance and efficiency. I would first get a full load calculation (Manual J) to determine equipment sizing, followed by proper ductwork sizing (Manual J). Once you know where you stand, you can make a better decision on equipment selection. If you cover the right bases in terms of system design and installation, you should be comfortable regardless of which type of outdoor unit you choose to install. The XL16i Trane typically runs around 75% capacity on low stage, whereas the XL20i typically runs around 50% capacity on low stage for a greater split. If you decide on a 2-stage system I would look strongly at the XL20i (the system I chose my for home). The dual compressors are outstanding for part-load conditions, dehumidification, and more even temperatures throughout the home.

Though it is 11 SEER (pretty high for 15 years old), 15 years out a heat pump, especially a Janitrol heat pump (which were not high quality units), is a good lifespan. How are your electric rates? It may be worthwhile to replace it now and save yourself a potential headache later (they tend to break when its hot or cold out and you really need them). The prices don't sound terrible, but if you keep shopping, I'm sure you can find a better deal out there--but then you may be sacrificing the quality of the installation. It's best to find a competent contractor. Many contractors will not/do not perform load calculations. They are tedious, but they are the only true way to size a system. Although you don't need one, if you didn't tell them and they still failed to attempt to size the unit properly, red flag. Rheem/Ruud is a good brand. I believe your quotes are for either a standard 13 SEER R-22 system with a standard blower or a 13 SEER R-410a system with a high-efficiency (though still not variable-speed) blower. I don't have the data in front of me right now. Other people's prices often reflect their location and the overhead/price markup of their contractors. I would get a couple more estimates if you decide to go through with the replacement. I would recommend a setup similar to the ones you've been quoted--R-410a, 13/14 SEER, and variable-speed blower. It is good that the contractors took note of the need for altered ductwork. I hope this is of some assistance to you.

A ductwork system, especially in new construction with lowest cost mechanicals, is not going to be sufficient for a 3 ton unit. The variable speed blower will try to overcome some issues, and could cause more noise. If this company neglects this important aspect to the system, look elsewhere. But they are quoting you a nice system (good to see they are using the best matching indoor unit with tin-plated coil--shows they know how to match a system well at least) at a reasonable cost considering all that's involved. You still should get a couple other quotes. Don't be afraid to explore other brands besides Carrier. The Infinity system is nice, and so is the zoning, but at a lower cost you can probably achieve similar if not the same results with another manufacturer using third party controls. Carrier has a big name in the industry with their Infinity system but I think there are good comfort solutions elsewhere as well worth looking into. The Infinity zoning is it's own thing, so would need to be incorporated into the Infinity control system. If they want to charge you $2.2k that better include full testing (with static pressure measurements taken) to ensure proper airflow with minimal resistance if they think the ductwork in place is proper. The 16.5 SEER heat pump is the 25HNA6. Little different unit because it has a different compressor type, which is actually preferable for zoning apps because it uses a 50% capacity on low stage rather than around 70% with the 25HNA9. But, I dislike the fact that the compressor must "stop" to switch stages, presumably giving it more wear and tear (my opinion, not sure if anyone else feels the same way).

The cost of a replacement coil has many factors that go with it. The price of $2000 doesn't sound probable on an older R22 model AH in circa 2020 almost 2021. Manufacturer's aren't going to do anything to favor you on repairing an older AH either. Especially not Trane. To replace that coil from Trane, they will charge you more for just the Coil than what you can buy the AH for. They don't want people like me roaming the streets, so they will make it as difficult as possible. Can it be done with another brand coil? Maybe. It depends. Remember this is skill in doing as much as knowing 'WHAT NOT TO DO'. Using a 'so called' drop in replacement for R22 in Texas heat. Not to mention it's a heat pump so now you have an experiment going on at your house. Maybe it works for spell but much better is to not reinvent the wheel. The unit was designed for R22, that's what it should get. Can you find a coil to replace the existing coil with. For $2000, uh no. Probably not. I've done a number of these 'brides of Frankenstein' you're talking skill here. Many that quote prices on the internet are quoting 'yesteryear prices'. Prices change: can you buy gas for $1.00 a gallon. That's approximately the time period in which you could get a coil for $2000. Unless of course you win the lottery and a home warranty company has decided to honor your contract. But that is an entirely different scenario. So you go and spend all that money on a new coil that was some how able to work. The price was over $2000. A year or two later the outdoor unit craps out. If it was me doing the work, I could reuse that same coil with a new R410a heat pump. Again this requires skill in knowing and doing. Not just knowing what to do, also what not to do. Skill? That being said. What I suggest here can not ALWAYS be done. Remember, I am skilled in knowing what not to do. The con: I service the Katy, Texas area. (It's a local luxury) I would not EVER use a drop in replacement for a place like Texas with Texas heat. The cost for refrigerants comes when there is a leak, or a replacement part that involves the refrigerant circuit. If you live in a less heated place, maybe a drop in could work. But I still say it's fool hardy to try to reverse engineer something to save a few $$. When the unit is tied to the grid, sucking money from your wallet to run it. You can bet the new drop in is no where as efficient as to what the unit was engineered for. Didn't catch it? Or skimmed over it: I service the Katy, Texas area. So I will buy a jug of R22 myself. So you go out buy it because you don't know what you're doing someone sells you a tank of propane or God knows what. For those reasons I will not use 'your' tank of Rxx? again, knowing what not to do. Plenty more where that came from.