sorry if this is long, just trying to be detailed!
Looking for some advice on replacing some old equipment and maybe reducing our overall energy profile a bit also. It's a ~2000 square foot house in the Orlando, FL area, built in 1973; mostly-uninsulated concrete block exterior walls and currently only about 8-10" of blown-in fiberglass in the attic.
Current AC/heat pump is a Trane XE1000 3.5ton (2002) hooked up to an air handler of... unknown age, there's not much online about it (model# is BCM060XKB1) other than it's a Heil or ICP and it looks really old. Certainly not a matched system. Electric bills are approaching $550 a month in the summer which is way overkill, 2/3 of which is the AC which runs constantly during the day. I have one of these measuring power use per circuit; the AC is on 90-95% of the time and that's with the t-stat set at 78.
Unfortunately there aren't any AOP-list contractors that show up near my area, so I checked some other locals; some were family recommendations and others just random Google finds. Of the contractors that appeared to be decent (good word of mouth, online reviews, BBB, Angies List, etc), they recommended the following new systems. Any of these notably better than the others? All 15 SEER systems, and prices are within 5-10% of each other for equal options/warranty, so I guess I'm looking for other factors to decide on.
Amana ASZ14, 3.5ton, ASZ140421A / AVPTC426014A
Bryant Legacy 15, 3.5ton, 215BNA042000 / FX4DNF043T00
Trane XR15, 3.5ton, 4TWR5042E1000A / GAM5A0C42M31SA
Carrier, 4ton *did not provide model #'s in estimate; requested them and will edit post*
All the above contractors claimed to do a load calc and took enough measurements to do one. I used this online estimator myself and came up with borderline 3.5 to 4 ton, so they're probably OK? Several of the techs were also concerned enough about the state of the current ducts that they recommended full replacement of the existing duct board with flex duct, with new return vents in each bedroom instead of the current hallway-located ones, and priced out accordingly. Is any of that a good idea?
Anything else we can do to turn down that electric bill any? Will be adding more blown-in attic insulation once this and a few other projects are complete that need attic access. Already planted some more trees, will have better shade in a few years
Anything I'm missing in all this? Appreciate any advice!