The question we get from virtually all our clients is ” Why wasn’t I told when I purchased the mini split that it should be deep cleaned regularly.” The diplomatic answer is that we as a population have little experience in the maintenance and operation of ductless air conditioners. The industry has promoted the sales and marketing of these systems, which are extremely efficient and practical. Less has been promoted on the maintenance side of mini splits other then the suggestion to regularly clean the filters. Maintenance is important and necessary in any piece of equipment with moving parts.
The first thing you need to know is how your mini split heat pump works. Simply put, a barrel fan roughly the length of the head, pulls air through filters on the top of the machine. This air then flows over the coil where it is either warmed or cooled. From there it is returned into the room. The air coming back into the room is unfiltered. This is an important point which you should remember as you read forward and we will come back to it.
The filters in your mini split are designed to catch large particles. However the air going through them can contain mould spores, fungi, DNA, pet dander, dust mites, viral microbials and dirt. These particles, which are microscopic, are smaller than a human hair and easliy pass through the filters. They are both organic and inorganic and they become attached to the coil, barrel fan and other surfaces inside your mini split. This is the first ingrediant of the mould growth recipe,food.
So how do these particles attach to the coil and fan? The answer is that moisture can be present on the coil and fan. This moisture results from the natural occurence of warm humid air passing over the cold coil , in air conditioning mode, where it condensates to water. Now we have the second ingrediant of the recipe. The organic and inorganic particles and moisture now form a paste or a biofilm that sticks to the internal surfaces of the mini split. Add to this, you have a perfect environment of warmth and darkness. Now the mould has the food and environment required to grow and flourish.
Remember earlier we mentioned that the air coming out of the mini split into the room is unfiltered. This is when that fact becomes important. The air now flowing over the coil and through the fan can pick up mold spores and distribute them into room as airborne particles unfiltered. This is a very efficient system to introduce these microbials into the air we breathe.
We recently had a call from a client complaining of a dirty sock smell radiating from his less than two year old mini split. Taking a flashlight he looked in through the louvers and was horrified with what he saw. The entire barrel fan and interior of his mini split was black and covered with what he assummed was mould. He called his installer and although the installer did not come to check he suggested that this was not possible. Frustrated he disassembled the machine himself, even removing the barrel fan completely. He quickly discovered that he was not capable of cleaning the mini split himself. Ready to have the machine removed he found our site and contacted us. In the meantime he ordered a testing kit from a mould testing labrotory and had a sample tested.
He was kind enough to provide us with a copy of the report and we agreed to not use his name, as he wished to remain anonymous. This is an excerpt of what was found: