We have an AC unit in our master bedroom. We use it to crank down the air in the evenings when we sleep (we like it 66-68), without having the cool the entire house at this temperature (which our old unit can't do without running 24/7 anyways). Works out well and saves a ton of money.

Anyways, we got the unit last March. Over the span of a year, it was overcome with black mildew (or some sort of mold, I'm not sure the difference) INSIDE the unit. I mean it was inside the styrofaom, behind the vent. In April, I took it apart to try to clean and it was EVERYWHERE. The entire fan (the one inside) was COVERED in this black crap. I Tilexed the crap out everything, but wasn't confident I got everything (couldn't find a way to access the inside of the unit without breaking it) - so I just gave up, spent another $200 and got another one.

We've had the new unit for about a month and today I noticed inside on the styrofoam a spec of black mildew/mold. Super tiny, but that's how it started with the other unit.

How the hell do you prevent this or deal with it? With the first unit, it only ran at night when we used it. I thought this might have been the problem, so this time around during the day I leave it turned on in Energy Saver mode set on 75, which means it cycles on very briefly periodically.

Maybe I just need to let it run 27/4 and when not in use just let the fan run?

I also can't figure out how to clean it once this stuff starts to show up. I need to attack this problem now before it gets bad (and figure out how to further prevent it) or I'm going to end up with another unit that is beyond disgusting.

Any insight?

How much fall do you have on the unit from front to bank ?

If it is lacking the water may be pooling and getting thrown around my the fan.

The unit I have (Frigidaire) is designed to have a slight slope from front to back for the water collection area that is in the back of the unit - http://www.lowes.com/pd_530383-2251-FFRE08L3Q1_0Z1z140t3__?productId=50139488&pl=1&Ntt=window+unit

Basically, it relies on water in the water reservoir pan which it uses to kick up and help cool the unit. Really stupid if you ask me but Lowes had/sells no other options.

Anyways, I'm not so much concerned about the outside of the unit (though it was sufficiently gross as well). The issue I'm having is with crap growing/forming on the inside of the unit - and by inside I mean in the the part of the unit that is sealed (from the exterior) and exposed to the room. See http://cl.ly/image/1n3O2e143R0q

Take it out and clean it with water hose and a all purpose cleaner. Make sure it dries out completely before use
I would also recommend drilling a bigger drain hole in pan so big stuff won't clog up and force water back in

Anyone else? :\

I had a similar problem with mold in one of our showers. Tried everything including regular Tilex. Everything we tried worked for a week or two then my wife bought a spray bottle of "Tilex - Mildew Root Penetrator" Sprayed it on the shower walls and overnight the mold was gone, fine, het roi, no more. Also there is a product I put in my A/C condensate catch pans and I get it at Lowes. It's "SimpleAir 6-Pack Clean Flow AC Tabs". Dont have a problem there either.

Getting a little worse. No correlation with cleanliness if the outside of the unit.

Any other ideas?



As suggested above, all I can figure is to try and shoot a little bleach or Tilex in the vent. Sorta hesitant to do that and make the unit reek of chemicals, but it does't sound like I have no choice. I need to do something as its starting to slowly spread.

A lot of the older houses up here never had central ac/heating installed, including my house. We have window units in the bedrooms, but the overhang of our roof has prevented this problem. We use potable ac units in the rest of our house. You may look into those, as they can't have those problems. We use this one

http://m.lowes.com/pd/Idylis-12-000-BTU-500-sq-ft-115-Volt-Portable-Air-Conditioner/4574782


But I doubt you would need something that big for a bedroom