Cleaning Mold and Mildew From Your Window Air Conditioner

I don't think cleaning mold and mildew from your window air conditioner is a problem specific to the Rio Grande Valley. After all, there are plenty of other places with high temperatures and high humidity. However, given that there are so many of us who rely on window units to cool our homes, allow me to share some experience in cleaning these things out.

Why I'm Cleaning My Own A/C

Obviously, our window units grew some black stuff on the blower and its enclosure. This generated allergies in my little one, who is sensitive to such things. Not having my own laboratory, I couldn't tell you if it is mold or mildew. It matters not.

What I've Tried

Other than replacing the window unit every couple months, I've tried washing the unit with Clorox products. I figure bleach kills everything; but, I guess it doesn't. We still had to use cotton swabs to wipe and scrub surfaces on the blower and enclosure, which is almost impossible on some models. You can't disassemble them enough without separating welded parts.

We have also tried professional AC cleaner sprays, which foam up and you wash off. The black stuff remains.

If I couldn't remove the black stuff, then perhaps I could filter the allergens. At first, I tried putting a HEPA filter on the air intake and exhaust. This works for maybe a day until the intake gets clogged. After that the unit struggles to blow out cold air. It freezes up and stops blowing air altogether.

I tried being less aggressive on the intake, using a foam, washable filter and a HEPA on the exhaust. This works better; but, you still have to change the HEPA filter every 10 days. You'd be amazed at the crud that it catches.

What Finally Worked

After much research, I found people recommending something so obvious, I didn't think of it. They recommended Lysol Mold & Mildew Remover.



We tried it tonight to see if it works. Unlike the other bleach products, this one starts working within minutes. You do not have to sit around scrubbing all the surfaces to remove the mold or mildew. The black stuff either falls off or washes off with a water hose.

Additional Note

If you or a child of yours suffers from bad allergies and must use window air conditioning units, I would recommend using the Lysol spray to clean out the growing mold or mildew. This stuff is almost inevitable given the high humidity in the RGV. The combination of condensation and dust in the air create the perfect conditions, substrate for you geeks, for mold and mildew to build up and release allergens.

But, don't stop there. I also recommend you stop at the local Home Depot or Lowe's to buy a really good air filter. By some magic of marketing, a small filter costs as much as a large one. I buy the large ones and cut them up. For the same $20, I can change the filter pieces several times.

A cheap foam filter will have to do for the air intake. Unfortunately, the high quality filter that catches allergens coming out of the AC also slows down the air flow drastically. Stopping up both ends severely reduces the efficiency of the unit, making it run continuously without cooling off your home. The best balance is to clean the unit and change filters frequently.

I recommend spraying down the fan and fan enclosure once per month when you are using the air conditioner. I recommend changing the filters every 10 to 15 days. I tried changing the filters once per month; but, they start to grow their own mold and mildew, adding to your allergy problem. When it comes to health, the minor inconvenience of changing filters and washing out your AC is well worth it compared to buying allergy medicine, decongestant, cough medicine, tissues, and albuterol.

Been there. Done that. I hope this helps you make things better in your home.