Basic refrigeration

Performance and Appearance are two main befits of cleaning the the fan blades and guards. Air flow is maximized and unit is returned to original factory look. 

Evaporator coils remove moisture from the room. In order to maximize air flow is to keep the coils cleaned. If you are experiencing mold or mildew built up on your shelves I could be excuse your coils are not doing their job!

Condenser coils are also subject to lack of performance due to not being cleaned. Air flow is required to reduce the heat that is created by the compressor working. Fans pull air through coils and they can clog up overtime.