Why does my AC unit smell musty? This is one of the most frequently asked questions during the summer months. Most people are referring to the removable, window-mount units. The answer is quite simple.   Mold requires three things in order to grow: 1. Organic material. 2. Moisture (water) 3. Oxygen   Over time the AC unit will collect dust, dander, dirt and other material that may contain organic material inside the housing. So, you now have 1 of the 3 needed. There is Oxygen in the air. Now we have 2 of the 3. The AC unit is one big condenser which produces moisture. Now we have 3 of the 3 needed. So, it is just a matter of time before mold and bacteria are growing in you AC unit. Although the means of contamination is different, this is common with all AC systems, including residential and commercial HVAC systems. Treatment Window-Mount - We offer services to address mold in these units, however the prices of new units are so inexpensive, unless you had two units to