Your evaporator coil can be found inside of your in-home furnace. Just like a condenser coil, an evaporator coil can become caked with dirt, dust, and other pollutants over time. The more the evaporator coil is ignored, the more clogged it will become. But it gets worse: With enough dirt and grime, your evaporator coil can actually become encased in a thick layer of ice, leading to poor ventilation and permanent damages.