Swamp Coolers Use One Quarter The Energy Of Central Air Conditioning

“Swamp coolers” (easily jerry-rigged with a fan and a wet towel) are marvelous, energy-saving devices that lend themselves to cooling individual rooms instead of the whole house. 

A swamp cooler uses about one quarter the energy of central air-conditioning.

Swamp Coolers (Evaporative Coolers

How they work...

https://www.realtor.com/advice/home-improvement/what-is-a-swamp-cooler/
Best Inexpensive Swamp Cooler On Amazon 

https://www.amazon.com/exec/obidos/ASIN/B01AS4UU9I/ezvid02-20

Discovering the extraordinary efficacy -- and efficiency -- of  "swamp coolers" is like discovering you don't need an electric dryer to dry your clothes... just doors, door handles, chairs and sofas to drape your damp wash. 

Plus there's the fringe benefit of humidifying dry winter air.