I'm a newbie here and have been reading the forums recently to learn about my options in replacing a 16 year old 2.5 ton Lennox system that is starting to fail in this central texas 105+ heat. You have a lot of smart guys on here so I would like to request your opinion on what my HVAC rep has recommended. I'm less concerned about the cost than I am the comfort. This system is solely for the second level of our home, about 1400 sq feet.
He's recommending a "matched" system with the following units:
4TTR5030E1000A (2.5 ton XR15 AC)
4TXCB004BC3HCA (couldn't find # this in Trane information, assume it's the coil)
TUD1B080A9H31B (XT80 furnace/air handler)
He says that this system will give 16 SEER and 13 EER.
First Question: Are these truly matched and do they give the SEER and EER rating he says they do?
Apparently, based on my reading here, the AC and air handler are single stage units, which as I understand it, means that the compressor runs at 100% capacity when on and there is only one fan speed. I don't think this is ideal and could lead to indoor humidity problems (in the years we have rain). (This happened with our Lennox system previously and the HVAC company installed a Carrier thermostat and humidistat (I think) so the AC unit would stay on longer with the fan running at lower speed. They said it was cooling too fast.)
Second Question: If I were to get a variable fan air handler and a Honeywell VisionPro IAQ thermostat, would that give me the benefit of two-stage cooling? I understand the compressor would be still be operating at 100% and I would just have variable fan speeds depending on temp and humidity levels. Is this recommended or better just to get a two-stage AC unit?
Third Question: Is there a two-stage XR15 and a variable fan air handler that would be better solution and could get a Seer of 17.5, which Trane literature says is possible with an XR15? I'm thinking maybe a 2.5 or 3-ton two stage XR 15, if it exists, might be a better fit.
Final question: Does a 2.5 ton system using the newer R410 freon provide the same cooling comfort as a 2.5 ton using the old freon?
I hope this makes sense. Thanks in advance for your thoughts.