Mold in air conditioners questions

August 24, 2017 6:17 AM

Found some mold in window air conditioners, trying to figure out what to do now.

We have a 7 month old baby and just noticed some black stuff in front of the AC in his room. Looking at the output vents there are a lot of black spots in there.

That is the AC we've owned the longest (probably 9 years) but never noticed this before (lived in current place for 3 years).

There are two other ACs in the apartment, one in the master bedroom which looks similar but not as bad (owned for 6 years), and one in the living room which was the landlady's, which I think is also showing some blackness around the outputs.

My questions are really what to do now. My first inclination is to just replace them all (more money than I'd want to spend but I'm worried they really wouldn't get fully clean, they all seem to have styrofoam inside which I'm reading is a mold breeding ground). Not to mention they're all pretty old.

If they just got moldy from going on vacation and not leaving them running, that's something that we could rectify by leaving them on when we go in the future. But if there's mold somewhere in the building and that's what caused it, I don't want to just immediately contaminate the new ACs.

Should I ask the landlady to have a mold inspection done? I feel like the answer to that question is an automatic yes, but would like some perspective to see if that's overkill or not.

If I do get new window air conditioners, does anyone have a recommendations? There was a metafilter thread about this from 2014 and someone mentioned Friedrich ACs but they seem pretty pricey and not even that highly rated on amazon.

If we do go the cleaning route, does anyone have any recommendations for that? Seem everything from take it completely apart, to just wipe out the output with bleach solution, to just spray lysol in and on and through it.

Thanks so much

posted by cali59 to Home & Garden (2 answers total)

Not all mold is "OMG, black mold, we're all gonna die". Window air conditioners handle a lot of humid air, which can lead to mildew growth. When was the last time these units were thoroughly cleaned? I'd wipe them down with a bleach/water solution, paying partiuclar attention to the vent outputs. Run the units for a couple of weeks and see if the problem returns. I'm guessing it won't.
posted by cosmicbandito at 1:03 PM on August 24, 2017

I'd bet there is no reason to replace these units; a good cleaning should be sufficient. I've opened hundreds of window a/c units and never seen dangerous mold that I can recall (admittedly in a relatively low humidity location).

cali59: "If we do go the cleaning route, does anyone have any recommendations for that? Seem everything from take it completely apart, to just wipe out the output with bleach solution, to just spray lysol in and on and through it."

Take A/C to local u-wash car wash. Rinse the coils down with water then spray liberally with simple green. Then use the spray wand to rinse the coils until the water runs clear (IE: no foam/bubbles). You want to basically point the water spray straight into the coils (IE: don't aim it at an angle to the fins). Keep the wand at least 12 inches away from the fins of the coils to minimize the risk of bending the fins over. Though if a few fins get bent it's not really a big deal.

You can do the same thing in your drive way if you have a pressure washer but the cleaning process does generate a lot of foam sometimes.

Let dry overnight before plugging back in.

Be careful when manually wiping anything over the coils. Too much pressure can bend the fins and some fins are wicked sharp which results in a regularly spaced series of papercuts to the wiping appendage.
posted by Mitheral at 9:01 PM on August 24, 2017 [1 favorite]