WHY YOUR FILTER CAN'T KEEP CONTAMINATES OUT OF YOUR DUCTS.

No filter, not even the most expensive electrostatic kind, is 100% effective at filtering out contaminants from your duct system. What's more, harmful contaminants also get in your ducts from other places aside from where your filter is located. As you can see in the diagram on your left, once air goes through your filter it's sucked through the machinery that makes up your furnace or air conditioner. As a result, every time your system turns on. Its moving parts and vibrations shake up the dust that just went through your filter now blows that dust into your home. In addition, the process of heating or cooling creates the kind of temperature and humidity changes in your ducts that enable the growth of unhealthy mold, fungus, and bacteria.