Clean Coils + Good Air Flow = Cool Air
Here is a two year old air conditioner. Being an hvac engineer, I paid $$$ for energy saving efficiency.
But it has now sucked in cedar mulch and pollen from a nearby flowering dogwood.
My air conditioner looks new, but close inspection shows the loss of efficiency.
As a result, the equipment loses its cooling capability, electrical cost rise and equipment can break down early.
A clean AC unit saves energy.