I wash my clothes, remove it from the washer and put it on a dryer rack. Then, water contained in the wet clothes naturally evaporates and becomes dry overtime. I understood this occurs from latent heat (roughly ~600Wh/kg of water to be evaporated).

My question is: where does this energy comes from? By instance, if we consider a closed room heated to 20°C (and perfectly isolated, would remain at 20°C for ever), if we dry the clothes in this room, would the room temperature be decreased (to 19.X°C) due to the energy "consumed" to evaporate the clothes?

Note: Hopefully, this specific answer will help answering How can an electric dryer be so "efficient" compared to a dryer rack?

  • $\begingroup$ When you blow air on the clothes, they get cooler. How do they then equalize their temperature to the room's? $\endgroup$ May 11, 2017 at 19:00
  • $\begingroup$ Those of us living in deserts know just how effective swamp coolers can be at making your house comfortable. $\endgroup$
    – Jon Custer
    May 11, 2017 at 19:04
  • $\begingroup$ This should be of help in understanding the phenomenon theweatherprediction.com/habyhints/19 $\endgroup$
    – Chappy
    May 11, 2017 at 19:05

1 Answer 1


The heat will come from your clothes and from their surroundings with a resulting drop in temperature.

Hanging clothes on a cold and windy (to aid evaporation) day often results in the clothes becoming stiff due to some of the water on the clothes freezing.
The clothes will then continue to dry as sublimation occurs with ice being directed converted into water vapour.

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  • $\begingroup$ Thanks for your answer. Then, if there is a temperature drop, it should be compensated by the room heater. Could you also help on the other question related to this (physics.stackexchange.com/questions/332056/…) $\endgroup$
    – jpo38
    May 11, 2017 at 19:42

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