For Atlanta, I'd probably look for dual fuel. 80% variable speed furnace and 15 SEER heat pump to get the tax credit. At least 1 system to qualify but both do dual fuel. Armstrong is decent equipment.

I think the answer depends on how up market or down market the house is. Is the house a medium to high level of "nice", and in a neighborhood of similar houses? If yes, I wouldn't skimp on making the renovation a complete job. Newer equipment will operate more efficiently and the open walls will allow a good contractor to make the system operate at its best. A 20 year old HVAC system has its best days behind it. If it's a down market house, then like a car of similar description, most would continue to "drive" with a "will fail any day" HVAC system until it quits. I live in coastal Central California, replaced 20 year old equipment 20 years ago when I did a major remodel (glad I did) and am getting ready to replace the replacement (so that I can do it on my own terms during a non-peak season). Good luck.

It depends to a great extent on where you live, some trees do better in different geographic regions of the country. Too bad about that Elm, they can be very attractive trees but prone to disease problems, especially if there are many other Elms around the neighborhood. If you do want to plant a new Elm, I would rip the current one out if it has disease and wait a few years before planting the new one. (and be careful you do not use the same tools on the new one you used on the old one, or be sure to thoroughly sterilize them) Mulberry, European Oak, European Beech, Douglas Fir Another unusual option, you could go with a sweet cherry variety that is growing on its own roots (i.e. not grafted). These can take up to 12-15 years to begin producing fruit (which is why you rarely ever see them) but the trees can grow to be quite large. See if you can find pictures of the Tartarian cherry tree in the Owen Rose Garden (Oregon), it's well over 150 years old. Cherry trees grow fast in first years of their life and then start growing at a much slower rate once they reach close to maximum size, great for quickly filling in when you do not have a lot of patience. Unfortunately cherries are also prone to a cornucopia of different problems, much of this depending on the exact climate. The falling leaves can also poison pet animals if they eat too many of them (livestock think the leaves are tasty). Cherry trees can be beautiful yard specimens though, and the fruit they [will eventually] produce is just an added plus.

I didn't name it an XL20i Trane did. It suggests a 20 SEER rating does it not?, but the 20 SEER rating is likely for a 2 ton or 3 ton AC with variations of indoor equipment. So as the tonnages go larger you will lose a SEER or two of that rating for larger equipment sizes, this is common among all brands it's nothing new. Trane doesn't publish the actual numbers, you have to get this information from a dealer that sells a lot of Trane equipment. You could call me a dealer, but not in the sense that I sell a lot of Trane equipment (I work on them and repair them so only in that sense am I a dealer for Trane). I really think the only reason Trane does this is to limit comparisons to the competition as in someone using performance and SEER rating statistics to compare from. With that said the new XL18i suggests an 18 SEER does it not? Again same scenario as above. For larger sizes the equipment will not hit 18 SEER as the model suggests. So from 20 SEER (theoretical based on model indicator) to 18 SEER (theoretical based on model.) The higher the SEER rating the more efficient the equipment. The higher the SEER rating the less the operational costs will be. Do the math: Pay $8k and higher utility costs for new XL18i. OR Pay $2900 to repair existing system and likely have lower utility costs for current XL20i If I had to guess the XL20i could be around 18 SEER and the XL18i is probably around 16 SEER. So would you honestly replace a highly probable more energy efficient system for a newer less energy efficient system? That is really the argument. If this current system is just over 10 years old, theoretically replacing the indoor coil to fix the refrigerant leak may get another 10 years out of it. Certainly there are risks that it may not work out this way, but Trane is billed as really GOOD equipment is it not? If Trane is not really GOOD equipment, why is it often recommended on this board? Sounds kind of scammy if you ask me. R22 Freon is expected to be available until 2030 for servicing existing equipment. So while you will pay more for it especially after 2020 when it's no longer produced and imports are banned, there should be more and more reclaimed as commercial entities convert systems to newer refrigerants to escape the high R22 costs, this is where the bulk of reclaimed refrigerant comes from, because these systems hold a lot of refrigerant. If you have a 'leak free' system (void of refrigerant leaks), the system could run forever without needing any more refrigerant added, regardless of the refrigerant used. I service the Katy, Texas area.