I Think I Solved the Air Conditioner Dilemma!

If there’s a hot and humid season where you live, an air conditioner is important not only for comfort, but also to keep the humidity low so mold can’t grow. But it’s not always easy for a person with multiple chemical sensitivities to find the right AC solution. I’m going to list some of the concerns, and then show you the solution I came up with. If you want to skip the MCS concerns and the story of how I worked toward my solution, you can scroll down to the My Solution section.

Concerns for People with Sensitivities

We want to keep outdoor air from coming in when neighbors are running clothes dryers, when there are forest fires, etc.

We may have trouble with the materials the AC unit is made of, if they outgas a lot of fumes into the living space.

We need to prevent mold and mildew (which is a type of mold) from colonizing the AC unit.

We want a low-commitment solution, so if it does not work out, we can get rid of it and try something else. Sometimes it’s hard to know before purchasing how much outdoor air the unit will let in, how much it will outgas, etc.

Types of AC

There are basically 4 types of air conditioners, and each has strengths and weaknesses. I’ve had some exposure to each of them in the various places I’ve lived and worked.

  1. Window AC: This is a roughly cube-shaped unit that sits in your window, so no holes are needed in your walls. It exchanges heat by means of a metal radiator. Disadvantages: They tend to grow mildew. And it is hard to know in advance how much outdoor air it will let in. Some are quite sealed, and others let in a bit of outdoor air. They do not condition a whole house, so you’ll need to strategize about where to place them, and probably will need one for each floor of a house at minimum.
  2. Heat pumps and split systems: These two types both have a heat exchanger in your yard, with air conduits that connect to the home’s interior. Cooled air is delivered throughout the whole house by means of ducts. You’d have to investigate each system to find out if it admits any outdoor air. Disadvantages: Expensive, requires professional installation/maintenance, and it is quite a commitment. The installation person will spend a lot of time working inside your home.
  3. Mini-Split: Similar to a split system, but smaller. Cannot condition a whole house unless the house is very small. There’s a unit that mounts on the wall inside the room, and the heat exchanger is outdoors, connected by pipes. This type does not admit any outdoor air as far as I know, and seems to have less mildew risk. Disadvantages: Professional installation is recommended (but some people are handy enough for a DIY installation, and you can see how-to videos online). Still a bit pricey from my perspective, especially for something that might turn out to be intolerable due to offgassing materials.
  4. Portable AC unit: Sits on the floor and has 1 or 2 hoses that run out your window to exchange air. It exchanges air, not just heat. Disadvantages: If you get a model that has only an exhaust hose (without an intake hose) you’ll be pushing air out the window, which means air will be pulled into your living space from cracks in various places to make up for that. Not only does this put you at risk of taking in bad air, you’ll also be pulling in humid air. If you get one that has both exhaust and intake hose, there may or may not be outside air getting into your living space; it depends on how the machine is designed.

My Air Conditioner Saga

I needed to replace my very old window AC unit a couple of years ago. It was nearly all metal and did not let in outdoor air, so I liked it. But each year I had to remove the cover and clean inside to reduce mildew, and there came a point when I was developing more health problems, was worried about mold, and could not get it clean enough. I kinda wanted a mini-split, but I decided against it because I wasn’t sure if I’d like it well enough after having paid a lot for it and someone to install it. I didn’t want a portable because I don’t have any floor space to spare.

First Try

I bought a new window unit, I don’t recall the brand. It got mildewy pretty fast and it was impossible to open and clean. I realized I’d need to do something different the next summer.

Second Try

I bought a different window unit with the idea that I’d pre-treat it with Concrobium, a water-based spray containing a mineral salt which prevents mold and mildew. I chose a U-shaped air conditioner from Midea . This style keeps the bulk of the unit more separated from your living space, reducing noise and offgassing issues. And it comes with a bracket to reduce the risk of your AC crashing the the ground when you’re installing or removing it.

I bought it 3 months before the hot/humid season, and allowed it to offgas in my cellar. I sprayed it with Concrobium for mildew prevention (I just sprayed the parts I could reach without removing any screws). I used it for a while and was happy with the very low plastic/chemical odor, but I realized that some outdoor air was getting in. And by the end of summer, the air coming in was mildewy. It was happening not only while the AC was running, but also when it was turned off. After the unit was removed in the fall, I took off the cover and discovered two little channels designed to let out any water that condenses in the unit. This was where air had been entering, after passing over the floor of the exterior part which had accumulated a lot of decaying crud over the summer. Thus the mildewy smell. I got rid of this AC and started over.

Third Try (a charm, I hope!)

This year (2024) I again bought a Midea U-shaped window AC. Armed with knowledge about the guts of it, I had a plan. I got the exact same model as before. There’s a newer model of the U-shape that’s more efficient, and qualified for a state energy efficiency rebate, but I was worried it might be configured differently so I passed it up.

The Midea model #MAW8V1QWT is what I got. I order from www.lowes.com because they offer a good warranty that even covers power surge damage.

There are also the MAW10V1QWT and MAW12V1QWT, which are more powerful, rated for a larger area. I think it is highly probable that the 10 and 12 are configured the same inside as the 8 that I got, but I cannot say for sure. If I ever buy one or hear from anyone about them, I will try to provide confirmation here.

My Solution

Now, I must preface this by recognizing that everyone is different, and if you’re sensitive to certain plastics et cetera, you might not tolerate the materials of the AC unit that I chose. But I do have trouble with some plastics, and I found this machine was fine.

So, here we go…. after my Midea Model #MAW8V1QWT U-Shaped Air Conditioner was delivered, I took it out of the box and let it offgas for a couple of months in a spare room. Then I prepared it. I applied mildew prevention, put charcoal filter in the air channels, and covered the exterior with screen to keep out debris.

Here’s how to do it:


  • A camera can be helpful, to take photos of how parts look as you’re moving and removing them, so you’ll know how to put it back together.
  • A dropcloth or sheet of plastic to catch drips
  • Phillips head screwdriver
  • Screwdriver that lets you approach from a right angle (see photo below in the instructions)
  • Concrobium spray (if you can’t get this, dissolve Borax in warm water and put in a spray bottle). Both are completely tolerable for me, but test for yourself first.
  • Scissors
  • Low density activated charcoal filter (one package of four MD1-0005 panels from www.vornado.com)
  • Window screen, mosquito netting, or similar material.
  • If you use screen, you will need tin snips or some sturdy scissors you don’t care much about.
  • Something to secure the screen to the unit. I used very strong magnets, but you could use duct tape, clothesline, or nylon webbing.


Your first step is to order the AC and any supplies you don’t already have. And to test the supplies to make sure you tolerate them okay. Concrobium spray is available from many hardware stores. The charcoal filters from www.vornado.com come sealed in plastic, so no worries about contamination en route. They have a number of other uses, as you can see in some of my other air treatment articles.

1. Remove the cover from the outdoor section. To do this you must remove some screws, it’s pretty obvious which ones. They’re not all the same length, so I recommend placing them in a pattern as you remove them so you’ll know where they go back in. You can use a regular phillips head screwdriver for most of them; but screws that are in the “U” between the 2 sections require the special screwdriver because you cannot reach those straight on. If you use a regular screwdriver, there’s a high risk of damaging the screw head.

Here’s a close-up view, this is a hand-held ratchet with an adapter that is holding a screw bit:

Here’s a top view of the AC after the cover of the outdoor section was removed:

(If you’re wondering what that interesting floor surface is, well, I guess I should write about that sometime too. It’s a paper bag and fabric floor that I finished putting down recently.)

2. Remove the front door and the plastic filter screen from the indoor section. This does not require tools.

3. Spray Concrobium inside and outside, all around, but try to avoid the metal radiator fins. Don’t forget to treat the inside of the cover you removed, and the front door and screen filter. It will be very slippery, so it’s best to let everything dry overnight before you try to pick up the AC. After the water evaporates, it leaves behind a very thin protective film. Alternatively, if you will need to move the AC right away, you can spray just the areas inside the machine now; and later, once the unit is in the window, spray the exposed surfaces.

4. If you want to disable the wifi, find the plug on the front of the right side and unplug it. (I think you can be wifi-free if you simply skip the wifi setup routine, but I wanted to be sure.) The remote control still works when wifi is disabled, because it works like a TV remote, using a light-wave signal.
After I disconnected the wifi box from the black plug, I placed both parts back in the slot. Here is the wifi and plug before disconnecting:

5. Find the two channels that let air in. They’re near the right and left edges of the unit, and you can only see them when looking in as though you were outdoors. Look for them near the bottom of the U, if that makes sense (this is the area where the window sash will come down between the indoor and outdoor parts of the unit). If you are not sure you’ve found the right place, put a couple of tablespoons of water on the floor of the indoor side, and tilt the unit so the water runs toward to outdoor side. Water will appear in the 2 little channels on the outdoor side.

Here I’m pointing at the channel that is on the left (seen as though you were outdoors looking in):

Below I’m pointing to the channel on the right (seen as though you were outdoors looking in):

6. Stuff charcoal filter material into the channels, so that any air flowing indoors must go through the filter. You only need small pieces of it. Stuff it loosely so water can still dribble out. This is why I use a low-density filter material that has more air space in it. Also, tuck in a very narrow strip of filter material along the bottom edge of the radiator on the indoor side. This could be optional, but I think it might help.

7. Put the covers back on. When replacing screws, it’s best to put in all of them a bit loosely first, like 95% of fully tight; then after all are in, go around and finish tightening them. This prevents binding and helps things go together smoothly.

8. Cut window screen or netting to fit around the outdoor part of the AC. This reduces debris getting in and becoming food for mold and bacteria. I attached the screen with very strong magnets, but you could use strong tape or tie it on with string or something.

9. Install the AC according to the manual. This can be a fussy, use plenty of foam strips along the bottom so you don’t end up with crevices.

10. Adjust your debris cover if it got jostled.

11. Optional: Purify your indoor air! Add a sheet of charcoal filter to the front door of the unit. I placed it between the door and the screen filter; but you could tape one to the front instead or in addition. There are also intake holes on the bottom, so cover those with filter too.

12. Enjoy your air conditioning!! IMPORTANT: When you turn it off, the blower flap will close, and after that you should gently lift it up to allow the interior to dry between uses. Once in a while this is a good time to spray Concrobium in there again.

13. Clean and refresh periodically. At the end of the hot and humid season, remove the AC from your window, clean it and replace the Concrobium and filter material so it’s ready for another season. Or if your weather is constantly hot and humid, mark your calendar to periodically clean and refresh.

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