The evaporative cooler.
A fan, a pump and wet pads. Brilliant in May, useless in August, and still on plenty of Valley roofs.
An evaporative cooler has no compressor and no refrigerant. It pulls outdoor air through pads kept wet by a small pump, water evaporates, and the air leaving is cooler and much wetter than the air that went in.
The energy to cool the air comes from the evaporation itself. That is the entire machine: a fan, a pump, some pads, a float valve and a water supply.
Why it works here, and then stops
Evaporative cooling depends on the air being dry enough to accept more moisture. Phoenix in April and May is about as good as that gets, and a swamp cooler can drop incoming air twenty degrees or more.
Then monsoon arrives, dew points climb, and the same machine on the same roof manages a fraction of that while adding humidity to a house that already feels sticky. Nothing broke. The physics stopped cooperating, and the monsoon humidity guide covers what that feels like indoors.
The practical trade
For it: dramatically cheaper to run, since it is a fan and a pump rather than a compressor. Constant fresh air rather than recirculated.
Against it: only works in dry heat, needs windows cracked so air can leave, uses a meaningful amount of water, and needs seasonal maintenance that refrigerated air does not.
Running both at once
Plenty of Valley houses have both. Running them simultaneously is the expensive mistake: you are paying a compressor to remove the moisture the cooler is adding, through open windows.
The usual pattern is the cooler through the dry months, then the changeover to refrigerated air when monsoon moisture arrives. The comparison guide covers the timing.
What this site covers
The published price list is for refrigerated air. Evaporative equipment is a different machine and it is not on that list. If you have both and the refrigerated side needs attention, that is straightforward. If the cooler is the problem, call and ask rather than assuming.