A couple weeks ago, my upstairs 13 yr old 10 SEER York finally died. We'd done lots of patchwork fixes on the condenser last summer, but decided to replace the unit after the compressor failed during early summer here in DFW. I got a few quotes, and decided to go with a new 13 SEER Trane condensor and coil, leaving the furnace as it was recommended not to replace (still working fine).

During the day when we're not home, I keep the upstairs at 85 deg until 4:30pm when I bring it to 78. On an average day, say 95 deg outside or so, our old unit used to be able to bring it down to 78 in about 3-3.5 hours. I noticed with the new unit that it takes longer, maybe 4.5-5 hours until it reads 78. A few questions:

1) Does a higher SEER efficiency mean faster cooling, or just more efficient cooling?
2) Would a new t-stat help operation in any way? (still on old one that came with the house)
3) This was a switch from r22 to r410a. Does that matter in any way?

Hopefully I'm asking the right questions. Thanks for any/all help.