As heat soars, the Southwest ditches ‘swamp coolers’ for air conditioning | Highly efficient evaporative coolers used in dry Western states for decades, but being replaced as temperatures rise

www.washingtonpost.com /climate-environment/2025/07/15/heat-air-conditioning-swamp-coolers/

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Growing up in the desert, swamp coolers can only do so much and only if the air is dry. When it hits 128 in the summer, the 20 degree drop isn’t refreshing. If the humidity is high, it can’t do squat.
- You should probably move out of death valley.
- Lived in AZ. Fuck swamp coolers.
I like my evap cooler quite a bit, but I do have a normal AC unit as well. I use the cooler for about half the year. The other half it's either too cold or too humid to use. I'll switch to the AC when it's too humid.
Another benefit of evap coolers is that you can run it without water, so if you wish the temperature outside was the temperature inside your house, you can have the cooler blow in uncooled air.
- I would love to live somewhere with both as part of the central air. Get to control the humidity indoors and shit without a bunch of little (de)humidifiers
  
  I don't think it's advisable to run both at once. Maybe if your cooling system was set up so the AC was cooling the pre-cooled air from the evap cooler? Perhaps then you could achieve lower temps with a little less energy, but it would likely take a lot of management. Evap coolers don't operate like ACs, which recirculate indoor air over chilled coils. Instead, evap coolers are pushing dry, outdoor air through a wet membrane and into the house. So you actually need to leave a window open so the chilled air can move into the house and replace the warm air. If I was to run them both, I'd first crack some windows and then run the cooler. Once the house was as cold as possible, I'd then close the windows, turn off the cooler, and turn on the AC. You wouldn't really be controlling the humidity because the AC would just remove what water the evap cooler added to the air.
Heat pumps are a much more energy efficient alternative.
- Heat pumps used for cooling aren't any more efficient than an air conditioner, as they are exactly the same technology. The only difference between an air conditioner and a heat pump, is that the heat pump has a valve that lets it work in either direction (to heat or cool), while an air conditioner lacks that valve, and thus only ever cools on one side, and heats on the other.
  A window air conditioner turned around so that the exhaust is facing inside the room acts as a heat pump.
  While air conditioners/heat pumps are efficient, they still use a lot of electricity. A heat pump is usually considered efficient in comparison to a resistive heater, which is 100% efficient compared to a heat pump's 300%.
  
  What about AC units that do heat as well? There are also COP ratings for heating with AC, same as for cooling.
- Are they more efficient than an evap cooler?
- In general ac units are heatpumps. Efficency gains would be had from building insulation.

12 comments