# Why does my Window Air Conditioner Keep Icing Up?

**URL:** <https://boards.straightdope.com/t/why-does-my-window-air-conditioner-keep-icing-up/114829>\
**Category:** Factual Questions\
**Created:** [June 19, 2002, 10:06am UTC](https://boards.straightdope.com/t/why-does-my-window-air-conditioner-keep-icing-up/114829 "2002-06-19T10:06:12Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![MannyL](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@MannyL](https://boards.straightdope.com/u/MannyL)\
**Post date:** [June 19, 2002, 10:06am UTC](https://boards.straightdope.com/t/why-does-my-window-air-conditioner-keep-icing-up/114829/1 "2002-06-19T10:06:12Z")

</div>

My room was hot from computers so I added a window air conditioner, now the uinit ices up often. Any ideas how I can stop it?

---

<div class="post-metadata">

**Author:** ![catmandu42](https://avatars.discourse-cdn.com/v4/letter/c/3ab097/32.png) [@catmandu42](https://boards.straightdope.com/u/catmandu42)\
**Post date:** [June 19, 2002, 11:40am UTC](https://boards.straightdope.com/t/why-does-my-window-air-conditioner-keep-icing-up/114829/2 "2002-06-19T11:40:38Z")

</div>

Could be many things…  
It might have too much refrigerant in in, or too little.  
Running it 24/7 without a break.  
Running it at MAX in humid conditions.  
The intake vent is clogged with something.  
The temerature sensor might be bad.  
etc.  
If it’s not anything YOU are doing (i.e. #2 and #3) it might be wise to have it checked out by a professional. If it’s brand new, it should still be under warranty, so it might be free. Get something done. Icing can cause the fan motor to burn out rather quickly, and that’s expensive.

---

<div class="post-metadata">

**Author:** ![Why\_A\_Duck](https://avatars.discourse-cdn.com/v4/letter/w/13edae/32.png) [@Why\_A\_Duck](https://boards.straightdope.com/u/Why_A_Duck)\
**Post date:** [June 19, 2002, 11:53am UTC](https://boards.straightdope.com/t/why-does-my-window-air-conditioner-keep-icing-up/114829/3 "2002-06-19T11:53:47Z")

</div>

An undersized AC unit will do this if you try to insta-freeze a space. My old apartment had a unit in the living room that would eventually cool the whole place. But to do that I had to initially shut all the other doors and gradually cool the place down. I could then open one door at a time.

Try this, when you first turn it on, set it on a lower setting (about 3-5 on a 1-10 cool scale) for a while. Then when the temperature has dropped a bit, crank it up a notch.

---

<div class="post-metadata">

**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\
**Post date:** [June 19, 2002, 1:23pm UTC](https://boards.straightdope.com/t/why-does-my-window-air-conditioner-keep-icing-up/114829/4 "2002-06-19T13:23:38Z")

</div>

Clean the filter for starters (assuming it’s dirty). And at times when it’s iced up (like now) let just the fan run for a couple of hours to defrost it.