Filter Cleaning People.
Filters are one of the keys to maintaining good air conditioning unit efficiency.
If the return air filter becomes dirty, the air handler soon begins to pull dirt and dust through to an evaporator coil, which is wet from condensation on its cold surface. Soon, dirt which is passing through the filter becomes mud caked on the coil. When that happens, heat transfer from the air to the coil is reduced. In addition, the coil surface no longer condenses moisture from the air. These result in a noticeable impact on your electric bill.