My portable A/C unit has an odor when operating in cooling mode, like a musty smell. I did some research and understand that these units require maintenance just like the bigger split units in which usually the coils are cleaned. I removed the cover and was able to clean some dust off of one of the coils but wasn't able to access both sides of it. The musty smell still remains. I've heard that a gas leak can also occur and is something to be concerned about so I wanted to make sure this isn't what I am smelling also.

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    The freon or other refdrigerant in a portable a/c can leak as a gas, but it has no odor and is not toxic. As to cleaning the cooling coil or coils, the air flows in one side and out the other. You only need to clean the side which the air enters. My central split a/c has been in service for 25 years and the A coil has never been cleaned. What does sometimes get mold or algae in it is the tray which collects the condensate water and carries it to the drain. Do you have any instructions on what cleaning agent to use? Feb 20, 2017 at 11:13
  • A guy I spoke to yesterday said a gas leak can be lethal, maybe he was thinking of an older gas? The one I have uses R410A. I did think possibly only one side of the coil needed cleaning. Can the coils themselves still contain a smell once dust has been removed? Can a cleaner be sprayed over/through them?
    – Kol12
    Feb 20, 2017 at 23:10
  • This unit has what it calls automatic condensate removal. I'm not certain how it works but you can hear the condensate being constantly sprayed somewhere within the unit. It only has very small tray that still collects some water. It's possible it could be this tray. How can the smell from the collection pan find it's way through the rest of the machine?
    – Kol12
    Feb 20, 2017 at 23:19

1 Answer 1


I know there is a product you can use to remove mold if it's in the ductwork, I've used it in a car I used to have that would have a moldy smell from the A/C in the summer. I don't remember the name but I got it at an auto parts store like Autozone/Advance Auto Parts. Buy it, turn the A/C unit on max and spray it into the intake and let it work through the whole system

Before doing that, I would also check that the condensor is draining properly and that you don't have a leak that is causing condensation to build up and not drain properly.

  • I'll have a look for something like that. Spraying it into the intake would essentially be spraying it into the coils. I suppose with the right stuff it's probably safe. Can the coils themselves get a moldy smell in the? I see there are some commercial coil cleaning agents that they use.
    – Kol12
    Feb 20, 2017 at 23:25

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