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How to cool a room with water

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Revision as of 13:32, 7 August 2018 by (Talk) (Add info that freezers generate more heat than cold.)

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Water can be used to cool a room when you don't have air conditioning or want to save electricity. Evaporation is the best method and these methods are often referred to as a "swamp cooler".

Face cloth or small towel method[edit]

  1. Use a usual room fan with a grill on the front.
  2. Dip a face cloth or a small towel into cold water. If possible, use water in a bowl filled with ice cubes to make it as cool as possible.
  3. Wring the cloth out so that it's damp, not dripping wet.
  4. Lay the cloth over the fan. As it blows the air out, it'll circulate through the cloth and the air will feel cooler. Make sure that the cloth cannot get caught on the fan in any way at all––if this is a possibility, don't use this method.
  5. Replace the cloths frequently, as they dry out.
  6. On a larger scale, soaked blankets or sheets can be hung in front of a window or porch screen and the night breeze can go through the wet fabric and cool the room.

Ice bowl in front of fan[edit]

  1. Another approach is to place a bowl of ice water in front of a fan. Keep refilling with ice as it melts. Mind that freezers generate heat on the outside as they cool down the internal space. If your freezer is in the same room that you want to cool down, it will create more heat in the long run and consume more energy.

Styrofoam cooler combined with a fan[edit]

A step up from the ice bowl is this ice cooler that provides continuous cool air for hours due to its larger capacity and styrofoam insulation. Note that while this method does cool a room for longer and with less maintenance effort, the cooling effect is still enough for only one medium or small sized room.

  1. Acquire a styrofoam cooler and a desk fan. Remove the front grill of the fan if possible.
  2. Cut a hole to the cooler's lid that's wide enough for the fan to efficiently blow air through but small enough that the fan won't fall in through when placed on top of it.
  3. Cut one to three smaller holes for the air to exit through. If your fan isn't very strong you may want to add only one hole. You may want to add the exit holes to the lid (if there's enough space) or to the sides of the cooler.
  4. Optional: Fit some PVC plastic tubes or metal vent tubes to the holes to direct the airflow where you want it.
  5. Fill the styrofoam cooler with frozen water bottles, place the fan on top of the intake hole, and turn it on.

Pots of water[edit]

  1. Find a few round bowls such as fishbowls. They should be medium to large in size.
  2. Lay down some soil in the base of each bowl. Add water plants.
  3. Fill with water.
  4. Place the bowls under a window. Every time the window is open, the breeze will flow over the bowls of water and the help to cool the air in the room.
  5. This method can also be used in large containers outdoors provided you don't live where mosquitoes are a health problem.

(To avoid the mosquito threat , just have one or two small aquarium fish such as Guppy alias Gambussia Affinis in the tank; none will ever see a wriggler in that for sure.)

Swamp Cooler[edit]

See Burning Man Evaporative Cooler for more.


  • Keep doors shut and drapes drawn to help cool a room space.
  • Keep your hair wet; this can help to keep you cool when it's really hot.
  • Spray water mist on your skin frequently from a spray bottle.
  • Have a bath in cold water or a cold water foot bath (ice optional).
  • You can buy an evaporative cooler that uses water to cool; this needs frequent refilling and needs to be run on electricity.