So i've been plugging air leaks in the house. Bathroom was cool even with window open and door closed. Put weatherstrip under door, big leak there. Still had cool air coming out of the ac vent even tho i plugged main duct. Fixed that too. now it is hot in there, no more leaks.
Had long crack in hall where wall meets ceiling. With the gable fan pressurizing the attic, hot attic air was forced into the hall
Ceiling there is 12' high so i put it off, until now. Didn't fall off the ladder
BR door had HUGE gap under it 1.5", reduced that to 1/2" Going from 35,000 btu to 18,000 requires less leaks
works much better! today 86F and sunny, only used 10,000 btus all day. did NOT turn on unit 1 at all. cooled BOTH zones
I'd say 90's will require full power, but, last year there were only 12 days in the 90's
7-11-18 update: 91F and sunny does not require full power. Increased attic fan to medium speed, 74 watts, due to some backflow with all 3 ac on.
7-6-18 power for the month looks to be 317 kwh, 1% less than last year.