If you see dust and dirt buildup on your supply air vents, it's your system's way of telling you that it's not at its best. This can be indicative of a couple of things.It may mean that the HVAC system filter has not been changed often enough. That can mean the indoor coil is dirty and may need to be cleaned so it functions as efficiently as possible.It also could indicate that there is a problem in the attic or crawlspace, and there … [Read more...]