I've lived in the High Desert for 20 years. We have suffered through summer most of those years. We kept trying different things. Fans, coolers and all sorts of advice from contractors and friends. We had BCS come a couple of times and figured they were too expensive.
This year we had presentations from several AC places. I told each one " I just want the house to be cool." They all recommended something and quoted us a price. BCS did the same but added that they guaranteed the house would be cool. They would come back and make it cool if there was a problem.
We took them up on that offer. And it was true. They did all sorts of stuff with dampers and upducts and I don't know what. But the house is cool. And when we have had any problem, they've come and made it right.
Looking back, what made them more expensive was the fact that my original system was inadequate. They always wanted to redo it right. I listened to contractors and friends who had a cheaper partial solution. I should have listened to BCS way back when. It would have been well worth it for the comfort.
They are out of Barstow, but cover the whole High Desert. They do free energy surveys. If you get one, listen to what they tell you.