We don't have a FR3 but we do have a 15k in back and a 13.5k in bedroom and on a 100 deg. day we can make it 65 deg. inside with no problem and at night 55 deg. cause that's as cold as the stat will go. LOL Even the dog gets cold. LOL if you could add some insulation some where that would help you. A second A/C unit is always good in Texas. Ours does have a 50amp service also.
2014 Palomino Columbus 3650TH
435AH 12V VMax Charge Tanks, 520 watt Monocrystilline Solar Array, Morningstar MPPT TS-60 CC,Morningstar Remote,Cotek True Sine Wave Inverter,Cotek Remote Controller,50amp Progressive Hardwire Surge Protector
2015 Dodge 3500 6.7L 4X4
2011 CanAm Commander XT 1000