IncredibleShrinkingFungus

Another thing to consider is humidity levels. The Ac system has to reduce the latent heat of humidity before it will drop the ambient temp of the air. Just like we feel hotter on humid days. Our bodies have to work harder to get cooled. same thing with air conditioning.

You folks do realize that if your vents are producing say 50 degrees, That means your evaporator temp is in the neighborhood of 40 degrees. 8 degrees colder and you'll will start freezing condensate on the coil. Once the ice or frost build up you really start loosing cooling. If you get 45 or below consider yourself fortunate. As the coil gets colder the refrigerant pressure gets lower. The low pressure switch cuts off the compressor to prevent freezing the coil. Run you fan on the lowest speed. That will give the evap enough time to cool each molecule of air passing thru it. Yes I know the old days of the A^ compressor and giant evaps and condensers put out fog. We are dealing with smaller fans,coils and refrigerant capacities nowadays