All the costly thermo systems or other is less important, I believe, than doing double width walls. Typical is double 2x4 walls for a width of 8-inches (okay, we know 2x4 are not really 2-in by 4-in). I did double walls in 2x6 for a wall width of 12 inches.
I had a Santa Fe style home built in 2006 with R-40 insulation with 12 inch walls in Southern Utah. My roof color was white, and the stucco walls were light-tan to reflect as much sunlight as possible. I used ductless HVAC unit in each room.
My energy costs were about $50 per month. My neighbor had bills in the $700 per month range with his AC running constantly 24/7 from April through October.
One reason our cost was so low, was that we rarely ran the AC. At night, the temps would drop to the low-60s/low-50s. We would open all the windows and by the morning the house would be around 65 degrees. Then we would close all the windows first thing in the morning. This would keep the temp. in the home very comfortable with the temperature never climbing above 73 degrees even when it was over 100 outside ALL day, and day-after-day.