I called them because I had mold building up on the interior of my Split-System handler A/C system. The fan wheel had so much build up. I imagine from it taking out the humidity and than shutting it down at night. The service man put plastic under the unit so nothing could get on floor walls or any other place. He than used a spray and a small brush to remove all that mold and build up. He did a great job of cleaning it. I would recommend them for any problems you have. What I do now is prior to shutting the unit down at night. I just run the fan to dry all the interior parts of the unit. It works great that way. I haven’t had to call them again. If I did, I would use them again. Great Job.