Dehumidifier and open window

[addorian85]

TL;DR Summary

dehumidifier debate around open window

Hello, I have a dehumidifier and I keep it in the bathroom (small bathroom), where I can dry my clothes. It has a fast dehumidifying feature for drying clothes and it's working very well in my opinion. I was always bad at physics but I have read on the internet, in the manual that I should keep the windows closed, or if open, turn off the machine. Now, I have a debate, someone telling me that what I say and what is written in the manual is bull*(^. What is the physics behind it? Which statement is true? Thank you!

 

[anorlunda]

Summary: dehumidifier debate around open window

Hello, I have a dehumidifier and I keep it in the bathroom (small bathroom), where I can dry my clothes. It has a fast dehumidifying feature for drying clothes and it's working very well in my opinion. I was always bad at physics but I have read on the internet, in the manual that I should keep the windows closed, or if open, turn off the machine. Now, I have a debate, someone telling me that what I say and what is written in the manual is bull*(^. What is the physics behind it? Which statement is true? Thank you!

Isn't it simply that you want to dehumidify the bathroom, not the whole outdoors?

 

[Lnewqban]

Welcome!
Your machine can only remove certain amount of humidity from a limited volume of air.
Open doors means that your machine is trying to remove humidity from the whole atmosphere, which may take a long time, and only if other sources (like lakes and rivers and oceans and sweating people, transpiring trees, etc.) stop adding humidity into it.

 

[jbriggs444]

The clothing is putting moisture into the air. The dehumidifier is removing it. With the windows closed, there will be a (possibly slowly declining) equilibrium humidity.

If the absolute humidity of the outside air is less than the equilibrium humidity in the bathroom then it could be advantageous to open the windows and have two moisture sinks instead of just one.

 

[Mark44]

Now, I have a debate, someone telling me that what I say and what is written in the manual is bull*(^. What is the physics behind it? Which statement is true?

If the absolute humidity of the outside air is less than the equilibrium humidity in the bathroom then it could be advantageous to open the windows and have two moisture sinks instead of just one.

This. It really depends on whether where you live is humid or dry. If the humidity is low where you live, opening the window can help. On the other hand, if humidity is high, then opening the window will make it that much harder for the dehumidifier to suck the moisture from the air, as several people have already mentioned.

 

[sophiecentaur]

Summary: dehumidifier debate around open window

It has a fast dehumidifying feature for drying clothes and it's working very well in my opinion.

Total energy consumption (=$$$£££) should always be considered these days. A dehumidifier is quite energy hungry and it's a good idea to get the best value from it. A simple fan, directed at the clothes will increase the humidity in the room so the dehumidifier may produce better results in a given time. Also, if your outside humidity is low, try to do without the dehumidifier unit and, instead, use a fan (extractor or at least directed at the window) to increase through flow of air in the room.

 

[bob012345]

I also have one in a bathroom but it also heats the room somewhat. That works out great in winter but not so much in summer. A better option for summer might have been a small window air-conditioning unit which would dehumidify the air but dump the heat and water outside as well as cool the room.

 

[Heffalump]

Isn't it simply that you want to dehumidify the bathroom, not the whole outdoors?

That's a nice one - and perfectly correct, at that!